A fascinating fact about hydrogen is that scientists estimate that hydrogen makes up over 90% of ALL the atoms in the universe.

In fact, 75% of the sun is made up of hydrogen and every second the sun consumes 600 million tons of its hydrogen atoms to make helium atoms and energy. That energy radiates out from the sun in all directions as electromagnetic photons.

These beautiful pictures from NASA are clouds of hydrogen gas floating about in the universe!

This week will be shining the spotlight on Helium, the second element in the periodic table. A fascinating fact about Helium is that it’s inert, meaning it doesn’t react with any other atoms.

With only 2 protons in its nucleus, helium is very light. Being inert and light, helium is the perfect gas for party balloons.  However, because helium is SO light, most of it just floats up into the sky and into outer space, making it extremely hard to find on earth.

However, scientists have recently found lots of helium emerging from under Yellowstone National Park. The helium is coming from deep under the earth where uranium atoms are continually decaying and releasing two protons from their nucleus. Those two protons   then pick up two electrons as they ascend through cracks in the earth’s  crust, thus creating helium atoms!

By the way, all that radioactive decay of uranium and other elements is what’s heating the interior of the earth.

Did you know that by adding a few atoms of lithium to flimsy aluminum foil it will turn the foil into a mixture of metals called an “alloy,” strong enough for building jet airplanes? It’s been known for thousands of years that sprinkling in a second metal atom makes strong alloys, but why? Because the lithium atoms act like speed bumps and prevent rows of aluminum atoms from easily rolling over each another and letting the metal bend.

Beryllium is used in the making of items like cell phones, missiles and aircrafts. 

Did you know that Mother Nature uses beryllium to make fine gemstones? Beryl is a crystal containing beryllium bonded to aluminum and silicate, but when a few atoms of chromium or vanadium happen to be included with beryl, beautiful green emeralds form. A few atoms of iron turn beryl into magnificent crystals of light-blue aquamarine, and a few atoms of manganese turn beryl into stunning pinkish-orange crystals of morganite!

Boron is one tough and versatile element. This element exhibits some properties of metals and some of nonmetals. Adding boron to steel produces a metal stronger than steel. Add boron to glass and you can make the glass resistant to heat, like the brand Pyrex. Boron nitride (boron bonded to nitrogen) is harder than a diamond, yet extremely lightweight. Boron’s high strength, light weight, and resistance to heat makes it the perfect element for building space shuttles and other aerospace vehicles. 

Boron’s not done there! Bonded to atoms of oxygen and hydrogen, it forms boric acid, a mild antiseptic and insecticide. Bond it to sodium instead of hydrogen and you get a familiar cleaner, Borax. To top it off, plants can’t live without boron. It is a micronutrient essential for plant growth. 


Did you know that carbon is a primary component of all life on Earth?   Carbon is the most versatile element in the periodic table, in large part because a single carbon atom can bond to up to four other atoms. When carbon atoms bond to each other, depending on how they are combined, they can form slippery soft graphite to open locks, incredibly hard diamonds, super strong sheets of flexible graphene that conduct electricity, and ridiculously tiny nanotubes far stronger than steel.

These nanotubes can be perforated with holes tiny enough to permit water molecules to pass through and someday allow us to obtain fresh water from the ocean. Thank goodness for carbon!

Did you know we can’t live without nitrogen? Almost 80% of the air we breathe is made up of nitrogen molecules, yet most of this nitrogen is immediately exhaled as we cannot absorb it in its gaseous form. 

Nitrogen moves from our atmosphere in a cycle that converts it to a form that can be absorbed by plants through their roots.  In this cycle, bacteria helps to break the strong triple bond that makes nitrogen inert and convert it to nitrogen-containing molecules that plants can use!

Have you ever wandered into the geology section of a natural history museum and noticed that every rock specimen has oxygen in it? You can thank cyanobacteria, the first bacteria to develop a way to capture the energy in sunlight and turn it into chemical energy, in other words, photosynthesis. 

They used the energy in sunlight to break water molecules apart into hydrogen and oxygen atoms which they discarded into the air. All that oxygen found its way into minerals in and under the surface of the earth so that today there isn’t a mineral in the ground that doesn’t have oxygen bonded to it. 

Now If only we could figure out a way to split water molecules as effortlessly as cyanobacteria, we’d have an unlimited supply of hydrogen to satisfy all our energy needs, and enough oxygen to purify our water supply, manufacture untold numbers of chemical compounds, and even power interplanetary space travel! 

Fluorine is a small atom but despite its size, fluorine is able to attract electrons with more force than any other atom in the periodic table. When fluorine atoms bond to long chains of carbon atoms (called fluorocarbons), no molecule can break the chain or even stick to them.  These long-chain fluorocarbons turned out to be the perfect molecule to coat pots and pans for easy cleaning (called “Teflon).”

Mesh fabrics made of fluorocarbons are waterproof because the empty spaces between the fine fibers is small enough to block water droplets from passing through. However — and this is key – the empty spaces between the fibers are large enough to allow molecules of perspiration to pass though. This mesh fabric even blocks wind by redirecting air molecules trying to pass through. By allowing fabrics to be waterproof and wind-proof, and still allow perspiration to escape, the newly-named “Gore-Tex” fabric, invented in 1976, spawned an explosion in the clothing and sportswear industry, as well as outdoor tents, and even space suits. ☔️ 🏔 ⛺️

Fluorine is a small atom but despite its size, fluorine is able to attract electrons with more force than any other atom in the periodic table. When fluorine atoms bond to long chains of carbon atoms (called fluorocarbons), no molecule can break the chain or even stick to them.  These long-chain fluorocarbons turned out to be the perfect molecule to coat pots and pans for easy cleaning (called “Teflon).”

Mesh fabrics made of fluorocarbons are waterproof because the empty spaces between the fine fibers is small enough to block water droplets from passing through. However — and this is key – the empty spaces between the fibers are large enough to allow molecules of perspiration to pass though. This mesh fabric even blocks wind by redirecting air molecules trying to pass through. By allowing fabrics to be waterproof and wind-proof, and still allow perspiration to escape, the newly-named “Gore-Tex” fabric, invented in 1976, spawned an explosion in the clothing and sportswear industry, as well as outdoor tents, and even space suits. 

Did you know that neon is not the only element used in “neon lights?” Neon gas is the only one that gives off reddish-orange light, but other elements, like helium,  give off orange light, argon – lavender light, and mercury –  blue light. The reason each element in the glass tube gives off a characteristic color is that when the electrical current flowing through the glass tube transfers its energy to electrons orbiting each nucleus, the excited electrons jump to a higher, more energetic orbit. When the electrons then drop back down to a lower energy orbit, they give off the difference in energy between the higher and lower orbits in the form of a light ray of one particular color. That energy difference varies slightly between different elements, hence the different colors emitted by each element!

Batteries provide an electrical current by removing electrons from atoms in the battery’s anode (-), and allowing the electrons to flow through a wire toward the battery’s cathode (+) where the electrons reattach to positive ions looking for electrons.

Lithium works well as a source of electrons, but lithium is expensive, not readily available, and difficult to get at, even when lithium deposits are discovered underground.

Sodium, in contrast is readily available and cheap, but has not served well as cathode material because there’s been no effective way to store the sodium ions once the electrons have left the cathode. Things have changed though. Prussian Blue, a pigment made up of iron atoms surrounded by “cages” of cyanide ions, is being redesigned to capture the sodium ions and store them while they’re being recharged with electrons.

So while sodium atoms may be too large to pack into tiny batteries for cell phones and the like, sodium may prove to be perfect for situations where size doesn’t matter, like storing solar energy captured by photovoltaic cells. Moreover, being less willing than lithium atoms to shed their electrons, sodium-based batteries are much less likely than lithium-based batteries to catch fire.

Did you know that without magnesium, we’d have no food? That’s because at the center of every molecule of chlorophyll is a magnesium atom, and without that magnesium atom, chlorophyll would have no way to capture the energy in sunlight and turn it into chemical energy.

Besides plants, all animals, including humans, depend on magnesium for protein and DNA synthesis, muscle contraction, nerve function, regular heart beats, and many other internal functions.

Magnesium’s most common industrial use is to strengthen aluminum. When atoms of magnesium are sprinkled into aluminum to form an alloy of aluminum, the magnesium atoms act as “obstacles.” When outside forces try to bend aluminum by forcing rows of aluminum atoms to roll over each other, the magnesium atoms stand in the way.

When it burns, magnesium gives off a bright white light, ideal for fireworks, flares, and special effects like lightning ⚡️

Aluminum is a versatile metal. It’s lightweight, doesn’t rust, conducts electricity, and when mixed with small amounts of other metals, aluminum forms strong, durable “alloys.” But, all this comes with a price: contamination of the air with carbon dioxide. Here’s why:

Aluminum starts out as aluminum oxide. Electricity is used to remove the oxygen atoms, but electricity produced by coal-burning plants spews carbon dioxide into the air. One way to combat this is to generate electricity with hydroelectric plants. An even simpler way is to recycle aluminum — something we can all do!

Silicon, the second most common element in the earth’s crust behind oxygen, is a very versatile element.

Silicon alone is the element for semiconductors chips. When bonded to two atoms of oxygen, it forms “silica” — sand 🏖 . When sand is heated, it becomes transparent glass as it cools. Adding boron turns glass into heat-resistant Pyrex, while adding lead improves the way glass reflects light. When silicon is bonded to four atoms of oxygen as “silicate” forms quartz crystals, which become blue amethyst gems when atoms of cobalt are added, green amethyst from atoms of chromium, and amber amethyst from atoms of iron. Adding methane to silicate creates silicone, used in everything from silicone oil to silicone grease, silicone rubber, silicone caulk, and even hair conditioners!

Pure phosphorus is hard to come by because it immediately bonds to oxygen atoms to form phosphates. In the mid-1600’s, though, Hennig Brandt discovered a way to remove the oxygen atoms from phosphates found in urine. Because the phosphorus he discovered glowed spontaneously, he called it “phosphorus” from the Greek — “bearer of light.” 💡

Phosphorus is widespread in our body. Calcium phosphate is the main structural molecule in our teeth and bones. The main source of chemical energy – in us and all of nature – is adeonsine triphosphate, ATP. Even our DNA is loaded with phosphorus. 🧬

Phosphates are an important component of fertilizers, but excessive run-off from farms contaminates rivers and lakes with excess phosphates that enhance the growth of oxygen-hogging and toxin-producing algae.

Pure phosphorus is still used to create flashes of fire in matches, fireworks, and incendiary bombs.

Sulfur bonds with almost every element in the periodic table to produce an enormous variety of products, but none with the breathtaking history of Charles Goodyear’s fanatic search during the 1830’s for a way to prevent sap of the rubber tree from becoming gooey in warm weather. Overcoming abject poverty and the death of multiple children, Goodyear finally, in 1839, mixed sulfur with the rubber sap and accidentally spilled some on a hot stove. What he peeled off the stove would become the start ofthe rubber industry.

Unfortunately, sulfur released from coal-burning power plants creates sulfur dioxide gas which combines with molecules of water in the air to form sulfuric acid, one of the components of the “acid rain” that’s helping to disintegrate marble statues, limestone buildings and monuments, and even steel structures. Commercially produced sulfuric acid, though, is used to make fe lizers, lead batteries, and wide variety of other useful products.

By the way, other sulfur compounds, like hydrogen sulfide, account for the nasty smell emitted by skunks and bacteria in our intestines.

At room temperature, chlorine is a gas – a very poisonous gas. It was used during World War I, but quickly abandoned when unpredictable air currents caused the gas to drift back over the troops that released it. Because of its toxicity, chlorine is still used in bleach to kill bacteria and viruses.

Chlorine’s strength lies in its very strong attraction for electrons, particularly the dense concentration of electrons found in double bonds. Those double bonds help molecules absorb particular light rays and reflect the rest as colors. It is this breaking of those double bonds that allows chlorine bleaches to be used to remove stains in clothing and in woods to make paper bright white.

Bonded to other atoms, chlorine is generally quite safe. Sodium chloride, for example, is table salt, and hydrochloric acid, HCl, is secreted by the stomach to help digest our food. Polyvinylchloride (PVC) tubes and pipes, ammonium chloride in batteries, barium chloride in fireworks, and ammonium perchlorate to power spacecraft into space are just a few examples of useful chloride compounds.

About 1% of the atmosphere is made up of argon. Being inert, argon gas is used during welding to keep oxygen away from the weld site and also used to store rare documents away from harmful oxygen.

Like neon, argon can be made to glow inside a glass tube once an electrical current strips an electron from it. Argon lasers are particularly useful for delicate eye surgery. Being heavier than oxygen and nitrogen, argon is better than plain air at insulating against heat loss in things like deep diving suits and double pane glass.

About 1% of the atmosphere is made up of argon. Being inert, argon gas is used during welding to keep oxygen away from the weld site and also used to store rare documents away from harmful oxygen.

Like neon, argon can be made to glow inside a glass tube once an electrical current strips an electron from it. Argon lasers are particularly useful for delicate eye surgery. Being heavier than oxygen and nitrogen, argon is better than plain air at insulating against heat loss in things like deep diving suits and double pane glass.

While calcium is known for building strong bones and teeth and hard shells for crustaceans, calcium has long been a vital building material for civilization. Calcium is mined from the ground as limestone, which is mostly calcium carbonate, mixed with some magnesium carbonate. Limestone is what marble
and chalk are made of, and also makes up the stalactites hanging from caves and dripping onto stalagmites pointing up from a cave floor.

Simply heating limestone drives off the carbon dioxide in calcium carbonate, leaving behind calcium oxide, called “quicklime.” Water added to quicklime turns it into “slaked lime” – calcium hydroxide. Slaked lime is used as a smooth paste to coat walls. Instead of just heating limestone, adding water and sand turns quicklime into mortar to bind rocks and other building materials together. Adding, in addition, iron and clay (a mixture of silica and aluminum), then heating the mixture into hard rocks and grinding it all into a powder creates “cement.” Then by adding water and rocks to cement, a slow chemical reaction begins that binds them all together into concrete.

Plaster of Paris is a close relative of limestone made up of calcium sulfate.

Scandium, named after its site of discovery – Scandinavia, is not only rare, but also difficult to extract from molecules. That’s why it took until 1937 to finally isolate pure scandium metal.

Scandium is close in size and weight to aluminum. That makes it the perfect element to scatter into molten aluminum and turn aluminum into a super strong alloy for jet airplanes, high-end bicycle frames, and even aluminum baseball bats.

Scandium iodide is used to alter sources of artificial light to make them appear more like sunlight.

What’s most astonishing about scandium is how many of its properties were predicted by Dmitri Mendeleev when he created the periodic table around 1869 and noted gaps in the table. Mendeleev not only predicted the elements that eventually filled those gaps, but also their properties. Scandium was one such element, situated beneath the element boron.

Titanium is lightweight but very strong. It is commonly used in aircraft, spacecraft, missles, ships, crutches, golf clubs, and high-end bicycles.

Titanium is also used in artificial joints because it bonds so well with bone without being rejected by the body’s immune system.

Oceangoing ships built with titanium hulls are much better at resisting rust and corrosion, because oxygen in the air reacts with titanium to form a barrier of titanium oxide.

Painters use titanium dioxide because it refracts (bends) sunlight in so many directions that sunlight reflects back as bright white. Titanium dioxide’s ability to reflect light like this is also why it’s used in sunblockers to help prevent sunburn.

Vanadium is a lightweight metal mostly used to make very strong alloys of steel without adding a great deal of weight, useful for things like piston rods, crankshafts, and axes. One of its key features is the large number of orbitals around the nucleus for electrons to occupy and move about in. Not only does this make vanadium ideal for large industrial batteries, but with so many orbitals for electrons to occupy, vanadium can manifest many beautiful colors. That’s why vanadium is named after the Swedish goddess of beauty, Vanadis. Vanadium’s many electron states may help explain why shallow-water animals like ascidians and sea squirts absorb vanadium from the sea, but vanadium’s actual role in those animals is still unclear. Also unclear is why Amanita mushrooms — those pretty but poisonous mushrooms with the red caps dotted with white spots — use vanadium to make a complex molecule called “amavadin.”

Chromium is the shiny metal that began being applied to automobile bumpers in the 1920’s, reaching their peak in the 1950’s. Chromium-metal is of especially high value for its hardness and for its anti-corrosive properties. When mixed with other metals, chromium is particular good at producing strong, rust-free alloys. Stainless steel, for example, is iron mixed with chromium, and sometimes with nickel and other metals.

The name “chromium” is derived from the Greek word for color, “chroma,” because with so many mobile electrons it makes rubies red, emeralds and sapphires green, and other compounds blue and violet. At one time, it was even used to make school buses yellow.

The electron mobility in the chromium atoms inside ruby crystals made rubies the ideal candidate to generate coherent light rays in the first laser, which was created by Theodore Maiman in 1960. While the role of chromium in human physiology is unknown, small amounts of chromium are still needed in our diet.

Manganese and iron are often found together in the earth as manganese and iron oxides. Not surprisingly, these two oxides have been identified as the first pigments used in prehistoric cave paintings. Another early use of manganese was to remove the greenish tint from glass and make it clear.

By bonding to stray atoms of sulfur in iron, manganese is able to strengthen iron into steel alloys strong enough for rifle barrels, train tracks, and prison bars.

Manganese’s ability to give and receive electrons makes it a useful component of enzymes. For example, all the oxygen we breathe is a byproduct of photosynthesis produced by an enzyme that splits molecules of water into hydrogen and oxygen. That enzyme, called the “water-splitting enzyme,” depends on its four atoms of manganese.

Fungi feed off of dead wood by digesting the lignin in wood with its manganese-containing enzymes. We depend on our manganese-containing enzymes to protect us from dangerously reactive atoms of oxygen “radicals,” and to ensure the growth of healthy bones. Too much manganese, though, can damage the brain and lead to Parkinson’s disease. In fact, the early studies of L-DOPA treatment for Parkinson’s disease were carried out on manganese miners.

High concentrations of manganese can be found in nodules lying on the ocean floor, just waiting to be mined.

Iron is the metal for strength. It may rust easily and it may not be lightweight, but it is strong and can also be hammered, tempered, annealed, and forged into practically any shape. Iron can be mixed with carbon to make different varieties of carbon steel, which can then be alloyed with manganese, nickel, tungsten, titanium, copper, vanadium, or chromium to make a wide variety of strong, corrosion-resistant steel.

Even hemoglobin uses atoms of iron to carry oxygen around our bodies. The iron in hemoglobin is why our blood is red. Iron is so essential to our diet that it’s even incorporated into breakfast cereals – check it out.

Iron is also great for making magnets, which is good news for us because the central core of the earth is mostly iron, much of it in liquid form, and as it flows, it creates a magnetic field around the earth that protects us from the harmful electromagnetic rays of the sun.

Cobalt is one of the three magnetic metals (iron and nickel are the other two). Of the three, only cobalt retains its magnetic properties at very high temperatures.

You may have heard of cobalt blue, but compounds of cobalt can range from violet to green to pink. Cobalt’s many colors make it useful for coloring glass, glazes, paints, and enamels. Not only is cobalt beautiful, it’s also strong, even at high temperatures. This makes it a very useful alloy metal.

Cobalt’s ability to move electrons around places it center stage in molecules of vitamin B12 where it performs much like iron does in hemoglobin. Cobalt’s importance to our health explains why farmers are often required to supplement cobalt-deficient soil with cobalt compounds.

Cobalt-60 is a man-made radioactive isotope of cobalt that gives off high-energy gamma rays that kill cancer cells.

Nickel is a transition metal that is incredibly resistant to oxidation and corrosion. Nickel can be mixed in with other metals to make strong corrosion-resistant alloys like stainless steel. The airplane and aerospace industries use nickel to make strong aluminum alloys. Nickel’s heat resistance produces alloys used in toasters and ovens. And don’t forget the nickel-copper alloy that makes up nickel coins! Nickel, like chromium, can also be plated onto other metals to produce a less shiny coat than chromium.

Nickel is also one of three metals that’s permanently magnetic, iron and cobalt being the other two, hence its use in rechargeable batteries.

Nickel and iron are often found together, especially in meteorites. One particularly large such meteorite crashed into Canada and around 1900, the English chemist Ludwig Mond discovered a way to extract the nickel. Mond found that by passing carbon monoxide gas though the mixture of iron and nickel to form nickel carbonyl, he could then gently heat nickel carbonyl into a gaseous vapor, which readily decomposed back into nickel and carbon monoxide. Great care must be taken handling nickel carbonyl, because once inhaled, both the carbon monoxide and the nickel are highly toxic and often fatal.

Copper has been mined and used for many thousands of years, because its relative softness allows it to be shaped into many different tools and utensils. Its real prominence began about 3300 B.C., when it was discovered that adding tin greatly strengthened copper into bronze.

The Stone Age quickly shifted to the Bronze Age, allowing civilization to begin building useful tools, especially agricultural tools. The Bronze age lasted until about 1200 B.C. when civilizations around the Mediterranean Sea began to collapse, and iron began to out-compete bronze.

Copper is still widely used, not just in our coins, but in many aspects of life. Its low cost and high conductivity of heat make it ideal for pots and pans. Its high conductivity of electricity makes it an important component of power plants, and its ductility allows copper to be pulled into thin electrical wires and shaped into delicate printed circuits.

Oddly enough, we need small amounts of copper in our diet to replenish key enzymes in our body, but more than that and copper turns poisonous. Various copper-containing insecticides, bactericidal agents, and antiviral agents use copper to poison insects, bacteria and viruses.

First discovered in Germany in 1746 by Andreas Marggraf, zinc has long been known to be a somewhat weak metal, but when combined with copper, it produces a beautiful and durable alloy called “brass.”

Zinc atoms have a particularly useful property: they’re willing to release their electrons. We take advantage of this property in a couple of ways. One way is to use zinc to coat other, more expensive metals and allow oxygen molecules in the air to bond with and corrode the zinc atoms instead of the more expensive metal underneath. Such metals are known as “galvanized” metals. Another way is to make zinc oxide (zinc bonded to oxygen), which happens to be a great sun-blocker when slathered on your skin. It’s so good at absorbing light and reemitting it that zinc oxide is also used by artists and commercial painters for especially bright white paint.

Zinc’s willingness to release its electrons also makes zinc ideal for generating electricity in electrochemical cells. In these cells, a zinc rod sits in one solution and a different metal rod sits in a separate solution. When a wire is attached to the two rods, electrons leave the zinc rod and flow as an electrical current that we can harness to do work. The zinc atoms that lose electrons undergo “oxidation” at the “anode,” while the metal atoms gaining electrons undergo “reduction” at the “cathode.” What makes zinc so admirable as an anode is that it is also willing, under the right conditions, to accept back any electrons generated by wind and solar energy and store them for later use.

Like iron, zinc atoms play an important role in a number of important enzymes in the human body, including alcohol dehydrogenase, a liver enzyme that breaks down alcohol before it can do any harm. Be careful with zinc supplements, though, as too much zinc in our diet can cause its own problems.

In 1869, before Gallium was discovered, Russian chemist Dmitri Mendeleev, the creater of the periodic table of elements, predicted gallium’s properties and its location below aluminum in the periodic table. Six years later, in 1875, gallium was discovered by a French investigator, Paul-Emile Locoq de Boisbaudran, who named it after his country’s Latin name, “Gallia”.

As a pure metal, gallium is soft and silvery, much like aluminum. Despite a rather low melting point of around 30 degrees Celsius, 86 degrees Fahrenheit — which suggests weak intermolecular bonding between gallium atoms — gallium has a very high boiling point – over 2400 degrees Celsius, almost 4400 degrees Fahrenheit. Its low melting point and high boiling point mean that gallium is liquid over a very wide range of temperatures.

Gallium’s usefulness is mostly confined to compounds of gallium, not pure gallium. Gallium arsenide and gallium nitride are both used to make semiconductors, much like silicon, only faster. They’re also used in solar cells to convert light into electricity, and in light-emitting diodes (LEDs) to emit light on receiving an electrical current.

Germanium was discovered by Clemens Winkler (a German chemist) in 1886, almost 20 years after Dimitri Mendeleev (creator of the periodic table of elements) predicted its existence.

One of the remarkable properties of germanium is its ability to bend incoming light, making it a valuable component of wide-angle lenses in cameras and microscopes. Fiberoptic cables also rely on germanium’s high index of refraction to rapidly conduct electromagnetic light waves. Oddly enough, germanium has no effect on infrared light and is thus used in special lenses such as night goggles and binoculars that detect infrared radiation.

Before silicon was found to be such a good semiconductor, germanium was the major semiconductor material in the 1950’s and 60’s. It still is favored in some electronic equipment because of its ability to vary the flow of electricity in response to separate (and tiny) electrical circuits. Like other semiconductors, germanium is also used in LED lights when brightness is important, such as car headlights.

Arsenic is a protoplasmic poison meaning that if a living cell is exposed to large enough quantities, the cell can be damaged or even killed. Arsenic mimics phosphorous (right above it in the periodic table) and can interfere with the body’s ability to assemble molecules of adenosine triphosphate, ATP, the most important energy molecule in the body.

Arsenic poisoning can be suspected by a darkening of the skin along with characteristic transverse (side-to-side) white lines in the victim’s fingernails. Chemical analysis of hair samples confirms the diagnosis.

Accidental arsenic poisoning was not uncommon in 19th century England when green arsenic compounds were incorporated into wallpaper. The damp English climate encouraged the formation of mold, which fed on the arsenic compounds in the wallpaper and released atoms of arsenic into the air.

In 1909, Paul Ehrlich led a group of research chemists in developing the first antibiotic, using arsenic as the key ingredient. The antibiotic was called Salvarsan which proved to be effective against syphilis. Ehrlich called it a “magic bullet.”

When bound up into certain compounds, arsenic appears to be beneficial to the growth and health of chickens. To be safe, though, In the United States arsenic compounds in chicken feed have been banned.

Arsenic in very low levels is fairly widespread in the environment. In certain places in the world, like Bangladesh, it has contaminated well-water.

Arsenic is used in the preservation of wood because it is effective in getting rid of unwanted fungi, bacteria, Doping wafer-thin layers of gallium or silicon atoms with atoms of arsenic that have “extra” electrons has been vital to the semiconductor industry. The doping process increases the conductivity of the semiconductor.

Selenium is essential for the proper function of certain key enzymes in humans, but more than a few hundred micrograms a day in our diet is toxic.

Added to clear glass, selenium adds a reddish tint, but at the same time it’s able to neutralize the greenish tint seen in glass contaminated with iron atoms.
When teamed up with sulfur, right above it on the periodic table, selenium lends a particularly foul odor to skunk spray.

What’s most interesting about selenium, though, is the discovery around 1870 that shining a light on selenium causes it to generate an electrical current.

It took Albert Einstein to explain in 1905 that light rays carry packets of energy we now call “photons.” The discovery of the electron a few years earlier allowed Einstein to propose that light’s photons were providing selenium’s electrons with enough energy to escape from their atoms and flow through wires as an electrical current.

Because selenium created an electrical current on exposure to light, selenium was commonly used by photographers in hand-held light meters to measure levels of light. Selenium’s real success, though, was in the development of the xerox machine in the late 1930’s and 1940’s. The key structure in the early xerox machines was a metal plate coated with selenium. The selenium layer was made electrically positive by a high-voltage instrument called a “Corotron.” When a bright light was shined onto the page to be copied, photons from the white areas of the page were reflected onto the positively-charged selenium surface, releasing selenium’s electrons which then neutralized the positive charges. Since the black letters on the page being copied didn’t reflect any photons, those areas on the selenium surface remained electrically positive.

The next step was to dust the selenium surface with tiny, black, negatively-charged toner particles which adhered to the positive charges on the selenium layer. Since the areas of positive charge represented the black letters on the page being copied, simply laying a sheet of white paper onto the selenium- coated plate and heating the paper fused the toner into the paper for a permanent copy. 

Bromine is a halogen – along with fluorine, chlorine, and iodine. There is no known function for bromine in the human body, and in fact bromine is quite toxic when the brownish-red gas is inhaled.

At one time, bromine was considered helpful for extinguishing fires and preventing fires when incorporated into flammable products like cushions, bedding, and drapes. In other compounds, bromine was the key element for killing insects, nematodes, bacteria, fungi, and even rats. Bromine also had a role in a variety of beneficial pharmaceutical agents. Bromine’s vast protective role was sharply curtailed once bromine was discovered to be destroying the ozone layer at a much faster rate than even chlorine.

Our curtailment of bromine use hasn’t prevented the oceans from incorporating bromine into a variety of compounds that are still harvested from highly concentrated sea water, like the Dead Sea and deep wells holding natural brine.

Krypton is one of the inert family of elements. It is heavier than helium, neon, and argon, but lighter than xenon. The discovery of krypton in 1898 was prompted by the finding that nitrogen gas prepared in the lab weighed less than nitrogen gas isolated from the atmosphere. Instead of postulating that the nitrogen gas prepared in the lab contained undetected amounts of a lighter gas, like hydrogen gas, Sir William Ramsay hypothesized that atmospheric nitrogen contained an undetected heavier gas.

Along with chemist Morris Travers, Ramsay tackled the problem by liquifying air with pressure and cooling, and then, by slowly reversing the pressure and temperature, allowing each of the elements in the liquified air sample to evaporate away in increments, a process called “fractional distillation.” Ramsy and Travers also removed the nitrogen from the liquidfied air sample by passing the air over very hot magnesium. When the residual gas was then subjected to electrical sparks, the spectrum of green and yellow lines revealed a new element that Ramsay and Travers named “krypton,” after the Greek word for “hidden.” This same methodology also led to Sir Ramsay’s discovery of two other inert elements: neon and xenon.

Krypton, like neon, is used to generate colored light. Neon lights are typically red, but krypton extended the range of neon-light colors into the greenish-yellow spectrum.
Despite being inert, krypton is still able to bond to the highly electronegative element fluorine. High-energy lasers use krypton fluoride to produce very bright lights for such things as airport runways.

Among the isotopes of krypton is the very rare krypton-85, which happens to be released during the testing of nuclear weapons. By keeping an eye on levels of krypton-85 in the air, sensitive monitors can detect secret nuclear weapon testing by an increase in atmospheric krypton-85.

Rubidium sits right below potassium and sodium in Group 1 of the periodic table. Like potassium and sodium, rubidium has a single valence electron that, because it sits in a high energy orbit far from the nucleus, is easily removed. This makes rubidium highly reactive. For example, rubidium, like the other Group 1 elements, reacts violently with water by replacing one of water’s hydrogen atoms to form an alkaline solution of rubidium hydroxide (RbOH). The released hydrogen atom bonds to another released hydrogen atom to form hydrogen gas.

When rubidium is heated, the excited valence electron gives off two frequencies of red color that are readily detected with a spectroscope. The red color is where rubidium got its name  – “rubidus”. The name is Latin for deep red, but its name has nothing to do with rubies, which are red because of chromium atoms.

Rubidium has very few commercial uses and no apparent role in plant or animal metabolism. However, because rubidium resembles potassium, which cells accumulate intracellularly, radioactive rubidium injected intravenously has been used to locate brain tumors. And that makes it pretty useful!

Strontium sits right below calcium in the periodic table and behaves in many ways like calcium. That’s why if strontium is ingested, it can be incorporated into our bones, especially the growing bones of children. This becomes a problem when the radioactive isotope strontium-90 is released into the atmosphere after a nuclear explosion or a nuclear accident like the ones that occurred at Chernobyl and Fukushima. The nuclear fallout enters the food chain by settling onto plants that are then consumed by farm animals. The danger of radioactive strontium-90 is that it can lead to bone cancer and damage the bone marrow’s ability to make blood.

The radioactivity emitted by strontium-90 consists of electrons that carry heat and conduct electricity, making strontium compounds a useful source of heat and electricity in isolated places like space vehicles.

Strontium-89 is also radioactive. When given to patients suffering bone cancer, the strontiuim-89 is taken up by the rapidly-growing cancer cells, which are then killed by the high dose of radiation.

Heating strontium atoms in a flame elevates its electrons to higher orbits. When the excited electrons return to a lower energy orbit, they give off a bright red color – hence the use of strontium compounds in fireworks and road flares. Certain strontium compounds glow in the dark because their excited electrons take their time to return to a lower energy orbit.

Yttrium was largely ignored until the mid 1980’s when superconductivity (resistance-free conduction of electricity) took a giant leap forward with the discovery that certain heavy elements allowed superconductivity to occur at 35 kelvins (-238oC). This was still ridiculously cold, but it stimulated the testing of other elements. When yttrium was tried, superconductivity rose to 90 kelvins (-184oC). Since then, other yttrium-containing compounds under very high pressure have raised superconductivity to even higher temperatures.
Yttrium is a key ingredient in synthetic “YAG” garnets, made up of yttrium, aluminum, and oxygen. The “G” in YAG garnets only refers to the resemblance of their atomic structure to that of natural garnet gems, not to the presence of actual garnet crystals.

Yttrium is used to make strong alloys of aluminum or magnesium metals, and even stregngthens the crystal structure of cubic zirconia gems.

Radioactive Yttirum-90 is used to treat liver cancer. High doses of Yttrium-90 are fed to the tumor cells via a catheter placed into the hepatic artery, the artery that supplies the liver.

The zirconium gem, zircon, has been around for thousands of years. This gem consists of zirconium atoms bonded to silicon and oxygen, and sparkles with a brilliance rivaling that of diamonds. Their brilliance is due to their high refractive index and the ability to rotate some of the incoming light rays, which produces a second image in the outgoing light rays, a property called “birefringence.” Zircon gems come in a range of colors depending on their impurities.
Zirconia, on the other hand, is a man-made product made up of zirconium and oxygen. Different shaped crystals of zirconia are made by heating molecules of zirconia and allowing them to crystallize during the cooling process. Zirconia crystals are strong, heat resistant, and corrosion resistant, ideal properties for lining the interior of furnaces, lining the pipes of nuclear power plants, as shields of space vehicles reentering the earth’s atmosphere, and for strengthening artificial hips and other prostheses, even dental implants.
Adding yttrium or calcium and magnesium while zirconia is being heated allows molecules of zirconia to form into cubic crystals as they cool. Cubic zirconia gems offer a beautiful and less expensive alternative to diamonds. To make cubic zirconia appear even more like diamonds, gaseous carbon atoms are allowed to settle onto the surface of a cubic zirconia. Adding color to cubic zirconia is done by sprinkling in atoms of chromium, nickel, copper, or titanium during the heating and cooling.

Niobium shares similar properties with tantalum (directly below it on the periodic table), and this is reflected in their names. Niobe, the Greek goddess of tears, was the daughter of King Tantalus.

Like other metals such as aluminum and titanium, niobium can be anodized, an electrolytic process in which oxygen atoms bond to the surface of anodes made of niobium, aluminum, or titanium. The thin oxide layer that forms provides a layer of protection to the underlying metal. In the case of niobium, the anodized layer also refracts light rays into many different dazzling colors, depending on the thickness of the layer.

When niobium is sprinkled into other metals, the resulting alloys are remarkably strong. The strength of such metals, combined with a layer of anodized protection, makes niobium alloys ideal for use in rockets, missiles, and high-speed aviation.

Anodizing niobium is the only way to get niobium to bond to oxygen, which means that unoxidized niobium in jewelry won’t tarnish when exposed to air or corrode when alloyed with titanium in orthopedic and dental implants.

When alloyed with tin, niobium permits electricity to flow with practically no resistance. At the ITER fusion reactor in southern France, a superconducting niobium-tin solenoid will soon be used to create an immensely strong magnetic field. The magnetic field will keep deuterium and tritium nuclei swirling about in a superheated plasma close enough to each other to fuse together and release neutrons in the process. The high-energy neutrons strike lithium atoms surrounding the plasma, generating heat and even more tritium nuclei to keep the fusion process going.
Unfortunately, niobium is quite dense, which caused it to sink below other, lighter metals when the earth was still molten. Hence, niobium is a rare find in the earth’s crust.

Molybdenum is a silvery-gray metal whose value lies in its great strength and resistance to high temperatures. Steel alloys using molybdenum, for example, are not only strong, they’re strong enough to withstand the high temperatures generated by high-speed drills and extreme compression.

Used in special industrial lubricants, molybdenum is key to preventing the lubricant from breaking down under very high pressures and very high temperatures.

Considering all the atoms in the periodic table, molybdenum happens to be a critical atom in a number of biologic enzymes, most notably, nitrogenase, the enzyme in “nitrogen-fixing” bacteria that splits molecules of atmospheric nitrogen into individual nitrogen atoms. Without nitrogenase, life on earth would be seriously crippled, because nitrogen would remain locked in the air as molecules of nitrogen and there there wouldn’t be enough nitrogen atoms available to make all the DNA molecules needed for genes or all the amino acid molecules needed for proteins.

Technetium was the first element to be artificially produced before it was discovered in nature – hence its name, meaning “artificial.” Since then, technetium has been discovered in very small amounts in uranium ores and in larger quantities in some giant stars. Technetium is rare on earth because none of its isotopes are stable, meaning all versions of technetium are radioactive and eventually decay into other elements. Most technetium on Earth is found in spent nuclear fuel rods.
Technetium is used frequently in nuclear medicine such as radioactive imaging and functional studies (in the form of Technetium-99m). Technetium-99m is useful for imaging because it emits easily detectable gamma rays, decays in 6 hours, and is so versatile that it can be paired with a range of biologically active substances depending on whether you are imaging the skeleton, the heart, the brain, or other organs.
Ruthenium is the first element in the “platinum group,” but the last to be discovered! This group is also known as noble metals because they are less reactive and more resistant to corrosion than other metals. All metals in this group share common characteristics, are rare in Earth’s crust, and are often found together with platinum in natural ores.
Ruthenium is commonly used in metal alloys to make the alloy harder or more resistant to corrosion. It is often combined with platinum or palladium to make electrical contacts with extreme wear resistance such as in chip resistors and high-capacity magnetic hard drives. Ruthenium alloys are also used to make surgical instruments and improve corrosion resistance of deep-water titanium pipes.


When alloyed with tin, niobium permits electricity to flow with practically no resistance. At the ITER fusion reactor in southern France, a superconducting niobium-tin solenoid will soon be used to create an immensely strong magnetic field. The magnetic field will keep deuterium and tritium nuclei swirling about in a super heated plasma close enough to each other to fuse together and release neutrons in the process. The high-energy neutrons strike lithium atoms surrounding the plasma, generating heat and even more tritium nuclei to keep the fusion process going.
Unfortunately, niobium is quite dense, which caused it to sink below other, lighter metals when the earth was still molten. Hence, niobium is a rare find in the earth’s crust.

Rhodium is the most valuable element you can buy and the rarest of the nonradioactive metals. Like the other metals of the platinum group, it is known for its catalytic abilities in speeding up chemical reactions.
Its main use is in automobile catalytic converters where it reduces the levels of toxic nitrous oxide in exhaust fumes by converting it to inert nitrogen and oxygen. It is also known for its shininess and resistance to corrosion. A micrometer-thin film of Rhodium is shinier than platinum, and these films are used to coat jewelry, mirrors, and searchlights.
Palladium is highly malleable and can be hammered into micro-meter thin sheets. Because it is highly resistant to oxidation and corrosion (like the other metals of the platinum group), it is sometimes used as an alternative to gold and silver leaf for gilding decorative objects. It is also commonly used in catalytic converters alongside Rhodium and Platinum, where it serves as a catalyst to convert unused fuel to carbon dioxide and water.
Palladium’s most unique characteristic is that it can absorb up to 900 times its own volume of hydrogen without applying pressure, so it is great for storing hydrogen (though very expensive due to its rarity).
Silver has long been associated with riches and glory and is known for being the most reflective metal (it’s commonly used in mirrors). But did you know that it also has antimicrobial properties, killing bacteria, fungi, and even some viruses?
Pioneers kept silver coins in their milk to keep it from spoiling on long journeys. Silver compounds like silver nitrate are now used to prevent infections in severe wounds and burns, added to bandages and cleaning products, and even sometimes incorporated into the fabric of socks to prevent odors.


Cadmium is an excellent electrical conductor and is most commonly used alongside Nickel in NiCad rechargeable batteries. However, these have largely been replaced by lighter, more powerful, and less toxic alternatives (such as NiMH batteries).
That’s right – Cadmium is toxic and must be handled with care! It is easily absorbed by the human body, where it can accumulate and cause kidney failure. It can also be harmful to the environment, so it’s very important to dispose of NiCad batteries properly. Instead of throwing them in your trash, NiCad batteries should be taken to designated collection centers, so they won’t wind up in landfills where the cadmium can leach into nearby water sources and cause environmental harm.
f you’re a fan of flat screen TVs and touchscreens on phones, tablets, or anywhere else, then you’re a fan of Indium.
Indium’s most valuable use is in the form of indium tin oxide (ITO) which plays a big role in our high-tech world. Touch screens, flat screen TVs, computer monitors, and solar panels all rely on liquid crystal displays (LCD’s). ITO is a transparent electrical conductor, which means electrical signals can pass throughout the screen without obscuring the image, making it a perfect match for these devices. Because glass is a poor conductor, it would make a poor touchscreen all on its own. But ITO adheres strongly to glass which, combined with its transparent and conductive qualities, makes it an easy choice for touchscreen coatings.


Tellurium is one of the rarest elements on Earth, and the least abundant of all metalloids (in-between elements that share characteristics with both metals and non-metals). Tellurium is less rare throughout the rest of our universe, however, and has even been traced to far away, ancient stars at the edge of the Milky Way. It is used primarily in metal alloys to add desirable properties. When added to stainless steel or copper, it makes the material easier to cut and shape. When added to lead, it improves strength, hardness, and resistance to corrosion. Tellurium can be found in semiconductors, solar cells, ceramics, tinted glass, infrared detectors, and so much more.

Iodine was used to make the first publicly available photograph – the daguerreotype, introduced in 1839. A silver-plated copper sheet was sensitized using iodine fumes, creating a light-sensitive silver iodide. Depending on the amount of light available, the photograph could require exposure for as little as a few seconds or up to 15 minutes – meaning it was not always feasible for human portraiture. Can you imagine sitting completely still for 15 minutes? The daguerreotype remained the most popular photographic process for 20 years, until cheaper and faster processes were developed.
Photography has continued to change dramatically since the invention of the daguerreotype, but any process that uses film (from standard photography to x-rays) is based on this process that was possible thanks to iodine!

This week we have another element that has been used in photography! (If you didn’t already know – science is a part of everything, even the arts!) One of the earliest uses of xenon was in flash bulbs. When xenon is exposed to the right amount of electricity, it produces an intense burst of light, perfect for flash photography!
In fact, xenon is used in lots of different types of lamps and lights. Today, xenon can be found in some movie projectors, lighthouse lamps, and car headlights. Because xenon emits a blueish glow when subjected to electricity, you can keep an eye out for the bright, white-blue headlights on some cars and know those are using xenon!

Did you know elements can tell time? Today’s element is so good at time keeping, it defines time. This is because cesium emits microwaves at such a reliable frequency, it has been used to establish the basic unit of time. More specifically, the official definition of the second is the time it takes for an atom of cesium to vibrate 9,192,631,770 times between two distinct energy levels. Atomic clocks that use cesium to keep time are so precise, it would take 1.4 million years to get even one second off!

Barium does not have many common uses in its purest form, instead being used mostly in either alloy or compound form. One common form is barium sulfate, used as a contrast agent in X-rays or CT scans.
The barium sulfate coats the esophagus, stomach, or intestine but is not absorbed by the body. It shows bright white when the body is X-rayed. This helps provide a clear picture of the internal organs to identify any abnormalities caused by disease or damage.
Barium sulfite is the form in which barium was first discovered, all the way back in the 1600’s. Vincenzo Casciarolo discovered barium sulfite in Bologna, Italy as a small pebble-like mineral. This little stone drew a lot of early attention because it would glow for years after being exposed to heat.
Lanthanum is the namesake for the Lanthanoids, a family of elements in the sixth row that share chemical properties. There are 15 consecutive elements that make up the Lanthanoid family, so keep that in mind as you check back on Table Tuesday for the next few months! You might hear this group of elements also called the rare earth elements – but in fact they are relatively abundant in earth’s crust!
They get this name because they are difficult to isolate. All metals in this group are silvery and highly reactive. They oxidize quickly which means they will tarnish when exposed to air and quickly lose their silvery appearance.
They are also relatively soft metals. Lanthanum is soft enough to cut with a butter knife!
Lanthanum is sometimes added to glass used in camera lenses to improve the clarity of the images it can produce. A lanthanum is also used in the production of flints for lighters. A lanthanum-nickel alloy is used to store hydrogen gas for use in hydrogen-powered vehicles. Lanthanum is also found in the anode of nickel metal hydride batteries used in hybrid cars.

The element cerium is so reactive, just scratching a knife across its surface results in a spray of bright sparks. This occurs because the tiny particles that are shaved off oxidize immediately in the air and combust, burning white-hot. This creates a small explosion which you see as a spark. This element is soft and ductile, like tin.

Cerium is the main component of mischmetal, a lanthanoid alloy used commonly in flints for fire starters. Mischmetal is also commonly used for special effects in movie car chases. In these cases, it is attached to the bottom of the car, where it produces a spray of sparks when it drags against the road.

Our next element is NOT didymium, though this compound did appear on Medeleev’s original periodic table. It was later determined that didymium was not an element itself, but composed of other rare earth metals, primarily praseodymium and neodymium (elements 59 and 60).

Both elements, and their combined form didymium, are commonly used to color glass. One such example is in safety glasses worn by blacksmiths and glass blowers, which are important for blocking out yellow light and infrared heat. Praseodymium, specifically, gives glass and enamels a bright yellow-green color. In fact, the name praseodymium means “green twin” in Greek. It is also used in high-power magnets and as an alloying agent in magnesium to make high strength metals.

Like its twin praseodymium, neodymium is often used to color glass. Unlike the yellow shade that praseodymium provides, neodymium colors glass several shades, ranging from purple to red to grey, and the color that you see can even change depending on the light and angle.

Beyond its use in coloring glass, neodymium is most widely used in magnets. Created when combined with iron and boron, these magnets are among the strongest permanent magnets ever created, with the ability to lift over 1,000 times their own weight. These magnets are commonly used in electric motors, power generators, computer hard drives, and audio equipment. You may even have seen sets of small neodymium magnets in a toy store!

Promethium was the last lanthanide rare earth element to be discovered in 1945.

It is also the only one that is radioactive.
In fact, all of promethium’s isotopes are radioactive, which means that the nuclei is unstable and naturally releases energy in order to achieve a more stable state.

Though Promethium is a silvery metal, it gives off a blue or green glow in the dark due to its radioactivity. Promethium is incredibly rare, and there is no known natural occurrence of the element in Earth’s crust.

There are no common uses of Promethium today, due to its rarity and high radioactivity. Promethium is generally found in the lab, where it is produced and researched for use in atomic batteries.

Samarium is the hardest and most brittle of the lanthanide rare earth elements.

Samarium was used in the first super-magnets that allowed for the miniaturization of electronic devices, creating things like headphones and personal stereo equipment. (In modern applications, neodymium magnets are more commonly used.)

Samarium magnets are great at maintaining their magnetic properties at high temperatures, so are still used in settings where this is required such as in microwaves.

Europium is one of the most reactive of rare earth metals, quickly oxidizing in both air and water. It also has a fun quality – it is phosphorescent, which means it glows when exposed to an energy source such as UV rays. Unlike fluorescent lighting, phosphorescence endures for some time even after the energy source is removed.

Europium glows red, and a compound of Europium is use frequently in both color television screens and computer screens. Europium is also used in European banknotes to detect forgery, as authentic Euros will glow red under UV light.

One particularly useful trait of our next element, Gadolinium, is its excellence at absorbing neutrons. Because of this, gadolinium is used in nuclear reactor control rods to regulate fission.

Nuclear fission, a process of splitting atoms to release energy, is used to produce electrical power in nuclear power plants. The fission process produces extra neutrons, which must be controlled to ensure that the plant continues to run effectively and safely. A special rod, made from gadolinium, is moved in and out of the nuclear reactor, controlling the number of neutrons that remain. By doing this and changing the number of rods inserted or how far they are inserted, the rate of the nuclear chain reaction can be controlled which allows control over the power output of the reactor.

Terbium is a silvery-white, rare-earth metal. The most interesting use of terbium is through an alloy made with iron and dysprosium called Terfenol-D. This alloy is used in a device that will turn any solid surface into a speaker. Terfenol-D expands or contracts in the presence of a magnetic field, and these contractions vibrate the surface it is placed on, turning that object (a window, desk, table, etc.) into a speaker. These speakers were originally developed by the US Naval Ordnance Laboratory for sonar systems but are now used in commercially available systems.

Dysprosium gets its name from the Greek word “dysprositos” which means “hard to get.” This might sound like the perfect name for a rare earth metal like dysprosium, but in fact it is not very rare at all in Earth’s crust. While it does not occur as a free element, it can be found dispersed among various different minerals and is twice as abundant in nature as tin! Instead, dysprosium’s name inspiration comes from how hard it was to separate from its source upon discovery.

Dysprosium is resistant to demagnetization at high temperatures, which makes it useful for magnets used in motors or generators. Today, dysprosium is often used in wind turbines and electrical vehicles.