148 Fun Facts About Periodic Table

Who is widely credited with publishing the first recognizable periodic table?

Dmitri Mendeleev, a Russian chemist, published the first generally accepted periodic table in 1869. He arranged elements by atomic mass and predicted the properties of undiscovered elements.

Which yellow element is the 'brimstone' of the Bible's fire and brimstone?

Sulfur is the Bible's brimstone, a word meaning 'burning stone': set alight, the yellow solid melts into a blood-red liquid and burns with a blue flame.

What do elements in the same horizontal row of the periodic table share?

Number of electron shells: each new row starts when a fresh, higher shell takes its first electron, so everything from sodium to argon has exactly three shells.

Which of these elements has the highest electronegativity?

Fluorine pulls shared electrons harder than any other element, 3.98 on the Pauling scale, which makes it so reactive that several chemists were injured or killed trying to isolate it.

Which category of elements are generally shiny, malleable, and good conductors of heat and electricity?

Metals owe these traits to a 'sea' of loosely held outer electrons that drifts between the atoms, carrying heat and current, reflecting light and letting layers slide instead of snapping.

What is the chemical symbol for gold?

The chemical symbol for gold is Au, derived from its Latin name 'aurum'. Gold is a precious metal known for its distinctive yellow color and resistance to corrosion.

What element is a liquid at room temperature and used in thermometers?

Mercury (Hg) is the only metallic element that is liquid at standard temperature and pressure, making it useful in devices like thermometers. Its symbol Hg comes from 'hydrargyrum', meaning 'water-silver'.

Which element is the lightest noble gas?

Helium is so light that Earth's gravity cannot hold it: once released into the air it drifts upward and leaks away into space, which is why the helium in a party balloon is gone for good.

Where in the periodic table do the alkali metals sit?

Group 1 also holds hydrogen, which shares the column but is not an alkali metal; the real members get more violent with water the further down you go.

Transition metals occupy which region of the periodic table?

d-block is the table's central slab, ten columns wide because a d subshell holds ten electrons; partly filled d subshells let these metals shift oxidation state and form vividly coloured compounds.

Moving left to right across a row of the periodic table, what generally happens to atomic radius?

Decreases: each step along a row strengthens the positive charge of the nucleus, which draws the electrons in tighter, so atoms shrink even as they get heavier.

Who proposed the law of octaves, an early attempt to classify elements?

John Newlands noticed that every eighth element resembled the first, like notes an octave apart; the idea was controversial at first and only later recognised as an important step toward the periodic law.

What is the primary role of valence electrons?

They participate in chemical bonding, which is why elements in the same column behave alike: they carry the same number of outer electrons. Mass and stability are the nucleus's business.

Which element has the symbol Fe?

The chemical symbol Fe represents Iron, which comes from its Latin name 'ferrum'. Iron is a common metal essential for both industry and biology.

What is the most abundant element in the Earth's crust by mass?

Oxygen makes up nearly half the crust by mass, not as a gas but locked into rock: almost every common mineral, from quartz to clay, is a compound of oxygen with silicon or metals.

Which noble gas glows orange-red when electricity passes through it in advertising signs?

Neon gives the classic orange-red glow; Georges Claude demonstrated the first neon lamps at the Paris Motor Show in December 1910, while signs filled with argon or mercury vapour glow blue instead.

Which element forms the backbone of every organic molecule, thanks to its knack for bonding stably with itself in long chains?

Carbon can bond to four neighbours at once, including other carbons, which is why it builds the chains and rings behind millions of known compounds, from methane to DNA.

Which gemstone is a crystal of pure carbon, the same element as the graphite in pencils?

Diamond and graphite are both pure carbon; only the bonding differs: each atom in diamond grips four neighbours in a rigid lattice, while graphite's flat sheets slide apart easily enough to write with.

What is the name of the horizontal rows in the periodic table?

Periods are the rows, and they show the table's key idea: read the elements in order and similar properties keep recurring, so each row ends where the pattern starts over.

Which element is a metalloid often used in semiconductors?

Silicon conducts poorly when pure but can be tuned by adding traces of other elements, which lets chips switch current on and off; California's Silicon Valley is nicknamed after it.

What is the chemical symbol for sodium?

Na stands for natrium, the Latin name drawn from natron, the Egyptian mineral salt; Berzelius introduced the symbol in his 1814 system of one- and two-letter chemical abbreviations.

Which element is added to table salt in tiny amounts to prevent goitre?

Iodine is added to table salt because the thyroid needs it to make its hormones; without enough, the gland swells into a goitre, and a shortage before birth can permanently harm a child's developing brain.

Gallium, found in 1875, had been forecast four years earlier under what placeholder name?

Eka-aluminium marked the empty box one place below aluminium in the 1871 table; when gallium turned up in a zinc ore, its density and its oxide matched the forecast closely.

Which metal has the highest melting point, at 3,422 °C?

Tungsten melts at 3,422 °C, the highest of any metal, which is why it was drawn into the white-hot filaments of incandescent light bulbs for most of the twentieth century.

Which element is crucial for bone health and found in dairy products?

Calcium phosphate is the mineral that makes bone hard: about 99% of the body's calcium, roughly a kilogram in an adult, is locked in the skeleton and teeth.

What is the common name for the elements in Group 17?

Group 17 elements are the halogens — fluorine, chlorine, bromine, iodine, and astatine — named from the Greek for 'salt-former' because they combine with metals to make salts such as sodium chloride.

Which element's symbol Sn comes from the Latin word stannum?

Tin, atomic number 50, takes its symbol Sn from the Latin stannum; the metal coats steel food cans and, alloyed with copper, gave the Bronze Age its name.

Which element makes up about three-quarters of the universe's normal matter by mass?

Hydrogen makes up roughly 75% of ordinary matter by mass and helium nearly all the rest, both left over from the Big Bang; heavier elements, forged later in stars, add only about 2%.

What element is used in old photographic film?

Silver halides, particularly silver bromide, were the light-sensitive compounds used in traditional photographic film and paper to capture images.

Which of these is a rare earth element?

Cerium is not rare at all: it is about as plentiful in the crust as copper or zinc and more so than tin or lead. The other three options are radioactive actinides.

What is the process of an atom gaining an electron called?

Reduction never happens alone: an atom can gain electrons only if another gives them up, so whenever iron rusts and is oxidised, the oxygen attacking it is being reduced.

Whose 1913 X-ray experiments established atomic number as the true basis for ordering the elements?

Henry Moseley's 1913 X-ray spectra showed each element's nuclear charge rises in whole-number steps, fixing atomic number as the ordering principle; he was killed at Gallipoli in 1915, aged 27.

Which silvery-white metal, prized for strength at low weight, goes into jet engines and hip replacements?

Titanium is as strong as steel yet far less dense, and it shrugs off corrosion, which is why surgeons and aerospace engineers both pay its price.

What is the chemical symbol for potassium?

K stands for kalium, the Neo-Latin name, which traces back through 'alkali' to an Arabic word for plant ashes; 'potassium' itself comes from potash, the ashes once boiled down in a pot.

Which element did Marie and Pierre Curie discover in pitchblende ore in December 1898?

Radium was announced by the Curies in December 1898, their second new element that year; Marie Curie and André Debierne later isolated the pure metal by passing a current through radium chloride.

Tennessine honours the home state of which national laboratory, which supplied the berkelium needed to make it?

Oak Ridge National Laboratory in Tennessee produced the 22 milligrams of berkelium required, which had to be rushed to Russia and bombarded before its 330-day half-life wore it away.

What collective name covers neptunium and every heavier element?

Transuranic elements all lie beyond uranium in the table; every one is radioactive, and neptunium was first made at Berkeley by bombarding uranium with neutrons.

What element is a component of chlorophyll?

Magnesium sits at the centre of every chlorophyll molecule; starve a plant of it and the plant strips the metal from its older leaves, which turn yellow between the veins.

Which element is named after a village in Scotland?

Strontium takes its name from Strontian, the Highland village whose lead mines yielded the mineral strontianite in 1790; its salts now give fireworks and flares their deep red.

What is the common name for the elements in Group 2?

Alkaline earth metals got their name from 'earth', the old chemists' word for a substance that neither dissolved in water nor changed in the fire; magnesium and calcium are the everyday members.

Which element's symbol Pb comes from the Latin word plumbum?

Lead's symbol Pb comes from plumbum, the Latin name that also gave English the word 'plumber', after the Roman workers who laid lead water pipes.

Copper is alloyed with which element to make brass?

Zinc makes brass, typically a third of it; tin is the one that makes bronze, which is the classic mix-up.

What term describes the energy required to remove an electron from an atom?

Ionization energy rises along each row and falls down each column, so metals such as sodium and potassium have very low values: they shed their one outer electron so readily that they react violently with water.

What is the only non-metal that is a liquid at room temperature?

Bromine is a dark red-brown liquid that gives off choking fumes at room temperature, so foul that its name comes from the Greek bromos, 'stench'.

Which element did Marie Curie name after her partitioned homeland?

Polonium, reported in July 1898, was named for Poland, which then had no independent existence, being split between Russia, Germany, and Austria-Hungary; Curie chose the name to publicise its plight.

Which gas is the third most abundant in Earth's atmosphere, at about 0.93%?

Argon makes up about 0.93% of dry air, behind only nitrogen and oxygen; nearly all of it is argon-40, produced by the radioactive decay of potassium-40 in rocks.

Which element, number 94, is the heaviest found in nature, if only in faint traces?

Plutonium forms naturally in uranium ore when uranium-238 captures stray neutrons, though only in faint traces; every heavier element known was first made by people.

Which element colours both rubies red and emeralds green?

Chromium does both: trace Cr³⁺ ions in corundum make ruby red, and the same ion in beryl makes emerald green; the element's name comes from the Greek chroma, meaning colour.

Einsteinium was identified in 1952 in the debris of what event?

Einsteinium turned up in fallout from Ivy Mike, the first hydrogen bomb test, detonated at Enewetak on 1 November 1952; fermium, element 100, was found in the same debris.

In 1937, which element became the first to be produced predominantly by artificial means?

Technetium, element 43, was confirmed in 1937 by Perrier and Segrè in Palermo from a molybdenum target irradiated at Berkeley's cyclotron; its name comes from the Greek technetos, 'artificial'.

Found by Marguerite Perey in 1939, which was the last element first discovered in nature?

Francium, element 87, was found by Marguerite Perey at the Curie Institute in Paris in 1939 as a decay product of actinium; she named it after France, her country.

Which metal melts at about 30 °C, low enough to turn liquid in the palm of your hand?

Gallium melts at 29.76 °C, so body heat alone turns a solid lump into a silvery puddle; the temperature is so repeatable that it serves as a fixed calibration point for precision thermometers.

Which hard, blue-grey metal is the densest stable element, about twice as dense as lead?

Osmium, at about 22.6 g/cm³, is twice as dense as lead; its name comes from the Greek osme, 'smell', after the sharp odour of its volatile, toxic tetroxide.

Clemens Winkler named the element he discovered in 1886 after which country?

Germany: Clemens Winkler named germanium for his homeland after isolating it from the mineral argyrodite in 1886; it matched the long-predicted 'eka-silicon' almost exactly.

Tungsten's chemical symbol W comes from which alternative name, used in German?

Wolfram is what most Germanic and Slavic languages call it; 'tungsten' means 'heavy stone' in Swedish, yet the Swedes themselves say wolfram.

Antimony's symbol Sb is derived from which Latin word?

Stibium was the Latin name for antimony's sulphide ore, ground up as the eye cosmetic kohl; Berzelius adopted Sb from it when he devised the two-letter symbol system.

The symbol Cu comes from a Latin phrase meaning 'metal of' which island?

Cyprus supplied so much of Rome's copper that the metal was called aes cyprium, 'metal of Cyprus'; the phrase wore down to cuprum, the root of both Cu and the word copper.

Yttrium, terbium, erbium and ytterbium are all named after a village in which country?

Sweden: in 1787 an army lieutenant picked up an unusually heavy black rock at Ytterby's quarry near Stockholm, and chemists went on to find new elements in it, four of them named after the village.

Which element, discovered in 1789, was named after a planet found eight years earlier?

Uranium was named after Uranus, spotted in 1781; neptunium and plutonium later took the next two worlds out, Neptune and Pluto, which counted as a planet until 2006.

Which element named after a continent is the radioactive source in many household smoke detectors?

Americium-241 ionises the air inside the detector so a small current flows, and smoke interrupts it; the element was named after the Americas because it sits directly below europium in the table.

Which element, named in 2016, joined seaborgium in honouring a person who was still alive?

Oganesson was named in 2016 for Yuri Oganessian, then 83, whose calcium-beam method had created the heaviest elements; only seaborgium, in 1997, had honoured a living person before.

Whose 1944 'actinide hypothesis' gave the heaviest elements their own row in the table?

Glenn Seaborg's 1944 idea pulled the heaviest elements out of the table's main body into a row of their own; in 1997 element 106 was named seaborgium, making him the first person honoured with an element while still alive.

In 1962 Neil Bartlett made the first compound of a noble gas using which element?

Xenon: Bartlett reasoned that platinum hexafluoride, which could already oxidize oxygen gas, might oxidize xenon, whose ionization energy is almost identical to O₂'s; the orange solid 'XePtF₆' followed in 1962.

The Haber process combines hydrogen with which element to make ammonia?

Nitrogen: the Haber–Bosch process, first run industrially by BASF in 1913, forces nitrogen from the air to react with hydrogen over an iron catalyst at high pressure to make ammonia for fertiliser.

The name cobalt comes from an old miners' word for which mythical being?

Goblin: miners blamed kobolds for an ore that looked promising yet smelted down to nothing they wanted; in the 1730s Georg Brandt showed it held a new metal, cobalt.

Nickel's name comes from a miners' curse on ore that yielded none of which metal?

Copper: Kupfernickel, 'Old Nick's copper' or 'copper-devil', was the miners' name for a reddish ore that looked like copper ore but gave none; in 1751 Axel Cronstedt extracted nickel from it instead.

Hennig Brand discovered phosphorus in 1669 by boiling down large quantities of what?

Urine: Brand boiled it down while hunting for the philosopher's stone and was left with a waxy white solid that glowed in the dark; phosphorus means 'light-bearer' in Greek.

Long called the heaviest stable element, which proved in 2003 to be faintly radioactive?

Bismuth was caught alpha-decaying in 2003, with a half-life near 2 × 10¹⁹ years, about a billion times the age of the universe; the title of heaviest stable element passed to lead.

Which is the rarest naturally occurring element in Earth's crust?

Astatine exists only as a fleeting step in the decay of uranium and thorium: even its longest-lived isotope is half gone in 8.1 hours, so no visible sample has ever been collected.

Which is the only lanthanide with no stable or long-lived isotopes?

Promethium, element 61, has no stable isotope; even the longest-lived has a half-life of only 17.7 years. It was named for the Titan who stole fire, a symbol of both the daring and the possible misuse of human intellect.

Bunsen and Kirchhoff found two new alkali metals in 1860–61 using which new technique?

Flame spectroscopy: Bunsen and Kirchhoff's new spectroscope split the light of flames into lines, and unfamiliar lines in mineral water and the mineral lepidolite revealed caesium in 1860 and rubidium in 1861.

A spike of which element in a clay layer pointed to the dinosaur-killing asteroid impact?

Iridium: the 1980 Alvarez hypothesis tied an iridium-rich clay layer at the Cretaceous–Paleogene boundary to an asteroid strike, since iridium is rare in Earth's crust but common in meteorites; the Chicxulub crater later matched it.

Vanadium is named after Vanadís, another name for which Norse goddess?

Freyja: Sefström chose her byname Vanadís for the element's beautifully coloured compounds; del Río had found it in Mexican 'brown lead' ore back in 1801, only to be talked out of his discovery.

Besides iron and cobalt, which element is ferromagnetic at room temperature?

Nickel joins iron and cobalt as the everyday magnetic metals; heat it past its Curie temperature, roughly 355 °C, and the magnetism vanishes. Gadolinium is magnetic too, but only below about 20 °C.

Which chemist isolated potassium and sodium for the first time in 1807, using electricity?

Humphry Davy used a voltaic pile to electrolyse molten potash and then soda at the Royal Institution in 1807, isolating potassium and sodium; in 1808 he added calcium, strontium, barium and magnesium.

The Hall–Héroult process of 1886 made which once-precious metal cheap to produce?

Aluminium was once costlier than gold. In 1884 a small pyramid of it capped the Washington Monument; two years later Hall and Héroult independently found the electrolytic process that made it cheap.

Hafnium is named after Hafnia, the Latin name for which city?

Copenhagen: Bohr's atomic theory said the missing element 72 should behave like zirconium, not like a rare earth, so Coster and Hevesy searched zirconium ore at his institute there and found it.

Discovered in 1925, which element is usually counted as the last stable one to be found?

Rhenium, named after the Rhine, was so scarce that its discoverers processed 660 kg of molybdenite to extract one gram; a Japanese chemist may have found it years earlier but mistook it for another element.

Gadolinium ultimately honours Johan Gadolin, a chemist from which country?

Finland: Johan Gadolin, professor at Åbo (Turku), analysed the black Ytterby mineral in 1794 and found the first rare earth, yttria; the mineral gadolinite was named for him, and the element followed in 1886.

Niobium is named after Niobe, daughter of which mythological figure with his own element?

Tantalus: Niobe was his daughter, and niobium is so chemically alike to tantalum that the two hide together in the same ores; Heinrich Rose chose the name to mark that family tie.

Which city, home of the GSI laboratory where meitnerium was first made, has an element named after it?

Darmstadt: its GSI laboratory made meitnerium in 1982 by firing iron-58 at bismuth-209, one of six elements first created there; element 110 was named darmstadtium for the city in 2003.

Who won the 1906 Nobel Prize in Chemistry for isolating fluorine from its compounds?

Henri Moissan isolated fluorine in 1886 by electrolysing potassium bifluoride in anhydrous hydrogen fluoride; he died in Paris in February 1907, two months after collecting the prize in Stockholm.

Which Scottish chemist won the 1904 Nobel Prize for discovering the noble gases?

William Ramsay found argon with Rayleigh in 1894, then helium, krypton, neon and xenon; his 1904 chemistry Nobel was paired with Rayleigh's physics prize for the same argon work.

Döbereiner's 1829 groupings of chemically similar elements became known as his what?

Triads: Döbereiner noticed that in groups of three such as chlorine, bromine and iodine, the middle element's atomic weight was roughly the average of the other two.

The 1862 'telluric helix', the first chart ordering elements by atomic weight, was devised by a French specialist in which science?

Geology: Béguyer de Chancourtois, a geologist at the Paris School of Mines, wound the elements around a cylinder so that similar ones lined up, but his paper was printed without the diagram and chemists overlooked it.

Which element, long used by rulers to murder each other, was called the 'king of poisons'?

Arsenic was tasteless in food and its symptoms passed for ordinary illness, so it stayed a favourite murder weapon until the Marsh test of the 1830s could finally detect it in a body.

Lawrencium honours Ernest Lawrence, the inventor of which machine?

The cyclotron: Ernest Lawrence invented it at Berkeley in 1930–31, and the accelerators that grew from it made most of the transuranic elements; lawrencium, element 103, is the last actinide.

Which body's spectrum revealed a new element in 1868, before it was found on Earth?

The Sun: Janssen and Lockyer each saw an unexplained yellow line in the solar spectrum during and after the 1868 eclipse; Lockyer named helium from helios, Greek for Sun, giving it a metallic '-ium' ending.

Who first recognised oxygen as an element and explained its role in combustion, before losing his head in 1794?

Antoine Lavoisier was guillotined in the Revolution; Scheele and Priestley had both isolated the gas first, Scheele calling it 'fire air'.

Who identified hydrogen as a distinct gas in 1766, calling it 'inflammable air'?

Henry Cavendish produced 'inflammable air' by dropping metals into acids and reported it to the Royal Society in 1766; Lavoisier later renamed it hydrogen, 'water-former', because burning it produces water.

Which is the least dense metal and least dense solid element under standard conditions?

Lithium, at 0.534 g/cm³, is about half as dense as water; it is one of only three metals that float on water, alongside sodium and potassium, though all three react with it.

Beryllium's early name, later dropped, referred to which taste of its compounds?

Sweet: the early name glucinium came from the Greek glykys, 'sweet', after the taste of beryllium salts, which are also toxic; the light, stiff metal now forms the James Webb Space Telescope's mirrors.

The US EPA ranks which radioactive gas as the second most frequent cause of lung cancer?

Radon: the EPA calls it the second leading cause of lung cancer after smoking, blamed for about 21,000 US deaths a year; colourless and odourless, it seeps from uranium-bearing rock into basements, so homes are tested for it.

The table's sixth row holds 32 elements because it includes which series, usually printed in a strip below?

Lanthanides belong between barium and hafnium, but printing them in place would stretch the table to 32 columns, so they are usually cut out and set below, with the actinides beneath them.

Which greenish-yellow gas, first taken for a compound, was shown in 1810 to be an element?

Chlorine: Scheele made the gas in 1774 but took it for an oxide of an unknown element; in 1810 it was shown to be an element in its own right and named from the Greek chloros, 'pale green'.

Oxygen, sulfur, selenium and tellurium make up which group of elements?

Chalcogens take their name from the Greek khalkos, a word that could mean ore, because so many metal ores are oxides or sulfides. Group 16 is completed by the radioactive polonium and livermorium.

Which element did Berzelius discover in a black mineral sent to him from Norway?

Thorium: Berzelius found it in a black mineral sent from Løvøya, Norway, and named both it and the mineral thorite after Thor; years earlier he had given the name to a supposed element that proved to be yttrium phosphate.

In 1967 the SI second was redefined by a transition in atoms of which element?

Caesium: since 1967 a second has been 9,192,631,770 ticks of caesium-133's hyperfine transition; the best caesium clocks would drift by under a second in millions of years, precise enough to run GPS.

Which gas, first on the periodic table, filled the airship Hindenburg when it burned in 1937?

Hydrogen is the lightest gas there is, which made it ideal for lifting airships but dangerously flammable. Modern blimps float on gas that cannot burn.

Which gas, named from the Greek for 'hidden', shares that name with Superman's home planet?

Krypton stayed hidden in ordinary air until 1898, when it turned up in the residue of evaporated liquid air. Superman's creators borrowed the element's name for his home world.

Which family of elements fills the far-right column of the periodic table and almost never reacts?

Noble gases have a full outer shell of electrons, so they have almost no need to bond with other atoms. They were long known as the inert gases.

Which metal is so malleable that a single gram can be beaten into a sheet one metre square?

Gold is the most malleable metal of all. Leaf made from it can be beaten thin enough to become semi-transparent, which is why astronaut visors carry a film of it.

Which soft, silvery metal explodes on contact with water yet makes up part of ordinary table salt?

Sodium on its own is too reactive to exist freely in nature, yet locked into salt it is the main source of the element in our diet.

Which synthetic element, first made in 1944, sits inside household ionisation smoke detectors?

Americium was a secret of the Manhattan Project until 1945, yet a speck of it now guards millions of homes. Smoke entering the detector disturbs the charged air it creates and trips the alarm.

Which precious metal, used in catalytic converters, names the award for a million-selling album?

Platinum was added as a US record-industry award in 1976 to reflect growing sales, with singles needing two million copies to qualify.

Which yellow element, the Bible's brimstone, gives skunk spray and garlic their smell?

Sulfur in its pure form has no smell at all; the stink belongs to its compounds. Its old name, brimstone, means 'burning stone'.

Which element, plentiful in bananas, do nerve cells need in order to pass on their signals?

Potassium takes its English name from potash, the plant ashes it was first isolated from. Too little or too much of it in the blood can upset the rhythm of the heart.

The atomic number of an element counts which particles inside the nucleus of each of its atoms?

Protons fix an element's identity: add or remove one and the atom becomes a different element entirely. Neutrons can vary without changing which element it is.

Which metal lends its name to the deep blue it gives to glass, ceramics and artists' paints?

Cobalt compounds have tinted glass and jewellery blue since antiquity, thousands of years before anyone knew a metal lay behind the colour.

Which element, first made in 1940, formed the core of the Fat Man bomb dropped on Nagasaki?

Plutonium for the bomb was manufactured at the Hanford Site in Washington state, then shaped into a solid core at Los Alamos.

What is a substance called when atoms of two or more elements are chemically bonded together?

A compound can behave nothing like its ingredients: water is built from two gases, one explosive and one that feeds fire.

What is an atom called once it has gained or lost electrons and so carries an electric charge?

An ion takes its name from the Greek for 'to go', because charged particles travel towards an electrode. Michael Faraday introduced the word in 1834.

On a standard periodic table, towards which corner do elements become steadily more nonmetallic?

Top right is where the nonmetals gather, while the opposite corner holds the most reactive metals. A zigzag band of in-between elements separates the two camps.

Which process, the energy source of every shining star, builds heavier elements out of lighter ones?

Nuclear fusion inside stars forged nearly every element in the human body, which is why astronomers like to say we are made of stardust.

Which country has two elements named in its honour, one of them from its old Latin name?

France is honoured twice over: once under its modern name, and once as Gallia, the Latin name a discoverer chose in 1875 for his native land.

Which element's oxide, grown as cubic crystals, is the best-known imitation diamond in jewellery?

Zirconium metal also clads the fuel rods in nuclear reactors, because it barely absorbs neutrons. Its sparkling oxide has rivalled diamond in jewellery since 1976.

Which element do patients swallow as a chalky sulfate 'meal' so that their gut shows up on X-rays?

Barium takes its name from the Greek for 'heavy', and its sulfate is dense enough to block X-rays. Its compounds also colour fireworks green.

Which element, number 96, honours a married couple who pioneered the study of radioactivity?

Curium was named for Marie and Pierre Curie. Its wartime discovery was first let slip in 1945 on a children's radio quiz show, days before the official announcement.

Which New Zealand-born physicist showed in 1911 that an atom's charge sits in a tiny nucleus?

Ernest Rutherford is known as the father of nuclear physics, and his portrait appears on New Zealand's hundred-dollar note.

Which founder of modern atomic theory also gave science its first account of colour blindness?

John Dalton studied his own faulty colour vision, and the condition is still called Daltonism in several languages. He drew each element as a circle with its own mark.

Which physicist, honoured by element 107, put electrons in fixed orbits around the nucleus?

Niels Bohr won the 1922 Nobel Prize in Physics for his work on atomic structure. His idea that electrons jump between set energy levels outlived the model itself.

Which physicist, left out of the Nobel Prize for nuclear fission, gave her name to element 109?

Lise Meitner worked out the physics of fission with her nephew, and their joint paper gave the process its name. She was nominated for a Nobel 49 times without ever winning.

Which rare-earth element gives its name to the strongest type of permanent magnet sold commercially?

Neodymium magnets were developed in 1984, by two companies working independently, and now spin the hard disk drives and cordless tools of everyday life.

Which element, number 5 on the periodic table, is added to glass to make it resist sudden heat?

Boron takes its name from borax, the mineral it was first isolated from. Glass made with it shrugs off thermal shock, which is why it is used for ovenware and lab flasks.

Which element, number 113, was the first to be named by a team of scientists from Asia?

Nihonium comes from Nihon, a Japanese name for Japan, where a team at the Riken institute made it in 2004.

Which element, number 112, honours the astronomer who moved Earth from the centre of the universe?

Copernicium was named on the 537th anniversary of Nicolaus Copernicus's birth. Its discoverers wanted to honour a scientist who changed our view of the world.

Which series of fifteen metals, elements 57 to 71, is printed beneath the main periodic table?

Lanthanides are pulled out into their own row only to keep the table narrow enough to fit on a page; they really belong inside period 6.

Diamond and graphite are different structural forms of one element; what are such forms called?

Allotropes can behave nothing alike: diamond is the hardest natural material, while graphite is soft enough to write with.

Which humorist set the names of the chemical elements to a Gilbert and Sullivan tune in 1959?

Tom Lehrer, a Harvard mathematics lecturer, borrowed the tune of the 'Major-General's Song' and ended by rhyming 'Harvard' with 'discovered'.

Which chemist and Auschwitz survivor titled each story in a 1975 book after a chemical element?

Primo Levi called the book The Periodic Table, and in 2006 the Royal Institution of Great Britain named it the best science book ever.

Which body, founded in 1919, is the recognised world authority on naming new chemical elements?

IUPAC gives each unnamed element a temporary name built from its atomic number, which is why element 116 spent years as 'ununhexium'.

Which light metal, number 4 on the table, is named after the mineral family that includes emerald?

Beryllium was named for beryl, the mineral it was first isolated from. Emerald and aquamarine are both varieties of that one mineral.

Which element, first found in 1817, takes its name from the Greek word for the Moon?

Selenium was named as a partner to tellurium, the element it closely resembles, which had already been named after the Earth.

Which element, named 'light-bearer' in Greek, glows faintly in the dark in its white form?

Phosphorus glows because its white form reacts slowly with the air. Its safer red form coats the striking strip on a box of safety matches.

Which California city, home to a famous university laboratory, gives its name to element 97?

Berkeley gave its name to berkelium in 1949. The same laboratory made californium the next year and named it after both the state and the university.

Which European capital, under its Roman name Lutetia, gave element 71 its name?

Paris was Lutetia to the Romans. Three chemists found element 71 independently in 1907, and the name chosen by Georges Urbain to honour the city won out two years later.

Which Swedish chemist introduced the modern system of one- and two-letter symbols for the elements?

Jacob Berzelius abbreviated the elements' Latin names, which is why several symbols look nothing like the English ones. He also coined the words 'catalysis' and 'protein'.

Which precious metal did William Wollaston discover in 1802 and name after a newly found asteroid?

Palladium honours the asteroid Pallas. Wollaston first offered the metal for sale in a small Soho shop without revealing that he was its discoverer.

Which rare-earth element, found in 1878, takes its name from the Latin name for Sweden's capital?

Holmium honours the home town of Per Teodor Cleve, the chemist who separated it from a brown residue while working on another rare earth. He used Holmia, the Latin name for Stockholm.

Which rare-earth metal is injected into patients as a contrast agent to sharpen MRI scans?

Gadolinium on its own is highly toxic, so each dose is locked inside a carrier molecule that the body can flush out safely.

Which German chemist, rival of the periodic table's Russian creator, drew up his own early versions?

Lothar Meyer and his Russian rival had both worked with Robert Bunsen. One early Meyer table grouped 28 elements into six families by their valence.

Which element, number 115, is named after the Russian region around the Dubna nuclear laboratory?

Moscovium is named after Moscow Oblast, the region surrounding the capital. A joint Russian and American team first made it there in 2003.

Which soft metal coats almost every flat-panel display as a transparent, conductive oxide?

Indium is named for the indigo-blue line in its spectrum, not for India. Most of the metal produced ends up as a see-through coating on screens.

Which metal, discovered by William Crookes in 1861, became notorious as 'the poisoner's poison'?

Thallium salts are nearly tasteless, which made them a favourite of murderers and of rat-poison makers. The name comes from its bright green spectral lines.

Which metal, named from the Greek for 'rose', is plated onto jewellery for a bright white finish?

Rhodium was named for the rose colour of one of its compounds, though the metal itself is silvery-white. A thin layer of it keeps jewellery bright and resists tarnish.

Which toxic metal gives its name to the vivid yellow, orange and red pigments loved by painters?

Cadmium was discovered in 1817 as an impurity in compounds sold in pharmacies. Besides paints, it colours glass and was long used to plate steel against corrosion.

Which rare-earth element was the first named, indirectly, after a person, a Russian mine official?

Samarium takes its name from the mineral samarskite, itself named for Vassili Samarsky-Bykhovets, who had let two mineralogists study samples from the Urals.

Which element, number 111, honours the German physicist who discovered X-rays in 1895?

Roentgenium is named after Wilhelm Röntgen, who labelled his mystery rays 'X' for unknown. In German they still carry his name instead.