99 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.

How many numbered columns does the modern periodic table have?

18 groups run from the alkali metals to the noble gases; the 1-to-18 numbering has been IUPAC's recommendation since 1988, and the 14 f-block columns are left unnumbered.

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

Elements in one period share the same number of electron shells; a new row begins each time a fresh, higher shell receives its first electron, so every period 3 element has exactly three shells.

Which of these elements has the highest electronegativity?

Fluorine is the most electronegative element, scoring 3.98 (often rounded to 4.0) on the Pauling scale; oxygen is next at 3.44, while caesium sits near the bottom at 0.79.

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

Metals are typically characterized by their lustrous appearance, malleability (ability to be hammered into thin sheets), ductility (ability to be drawn into wires), and excellent conductivity of heat and electricity.

What is the atomic number of carbon?

Carbon (C) has an atomic number of 6, meaning each atom of carbon has 6 protons in its nucleus.

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 (He) is the lightest of the noble gases, with an atomic number of 2. It is also the second most abundant element in the universe.

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?

Transition metals are located in the d-block of the periodic table. These elements are known for forming colorful compounds and having multiple oxidation states.

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

Atomic radius generally decreases as you move from left to right across a period. This is because the increasing nuclear charge pulls the electron shells closer to the nucleus.

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

John Newlands proposed the law of octaves in 1865, noting that every eighth element showed similar properties; the Chemical Society of London declined to publish it and contemporaries ridiculed the musical analogy.

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 is the most abundant element in the Earth's crust, making up almost half of it, primarily in the form of various oxides.

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 makes chains, rings and some ten million known compounds; no other element comes close.

What is the name of the vertical columns in the periodic table?

The vertical columns in the periodic table are called groups. Elements within the same group often exhibit similar chemical properties due to having the same number of valence electrons.

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

The horizontal rows are called periods; a new period begins each time an electron first enters a fresh shell, so the seven periods match the seven occupied shells of the heaviest elements.

Which element is a metalloid often used in semiconductors?

Silicon is a metalloid, meaning it has properties intermediate between metals and nonmetals. Its semiconducting properties make it crucial for computer chips and other electronic devices.

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; iodine deficiency affects around two billion people and is the leading preventable cause of intellectual disability.

The element predicted in 1871 as 'eka-aluminium' turned out to be which?

Gallium, discovered by Lecoq de Boisbaudran in 1875, matched Mendeleev's 1871 'eka-aluminium' forecast in density, melting point, and oxide character, four years after the prediction was published.

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 served as incandescent light-bulb filaments; among pure metals it also has the lowest vapour pressure.

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

Sardines, kale, and soy products are also rich in it.

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.

Hydrogen makes up roughly what share of the universe's normal matter by mass?

75% of ordinary matter is hydrogen and most of the rest is helium; its commonest isotope, a lone proton, carries the rarely used formal name protium.

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: at 68 parts per million it is the 25th most abundant element in the crust, more common than copper. The other three are actinides.

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

The process of an atom gaining one or more electrons is called reduction, resulting in a more negative charge. Conversely, losing electrons is oxidation.

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 at about half the weight and shrugs off corrosion, which is why surgeons and aerospace engineers both pay its price.

What is the chemical symbol for potassium?

Kalium traces back through 'alkali' to the Arabic al-qalyah, meaning plant ashes.

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

Radium was announced by the Curies in December 1898 from pitchblende residues mined at Jáchymov (Joachimsthal); Marie Curie isolated the pure metal by electrolysis with André Debierne in 1910.

Which superheavy element is named after a U.S. state?

Tennessine (element 117) honours Tennessee, home of Oak Ridge National Laboratory, which supplied the berkelium target for its synthesis; the name was approved in 2016 and it sits at the bottom of the halogen column.

What is the name given to elements beyond Uranium (atomic number 92)?

Elements with atomic numbers greater than 92 (Uranium) are known as transuranic elements. They are all radioactive and, with the exception of trace amounts of Neptunium and Plutonium, are not found naturally on Earth.

What element is a component of chlorophyll?

Its presence there, found in 1906, was the first time the element had been detected in living tissue.

Which element is named after a village in Scotland?

Strontium takes its name from Strontian, the Argyll village whose lead mines yielded the mineral strontianite; Adair Crawford recognised it as a new earth in 1790.

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

Alkaline earth metals got their name from the old word 'earth' for an oxide that would not melt; 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 is the minimum energy required to remove the most loosely bound electron from a gaseous atom or ion. It's a key periodic trend.

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

Bromine is the only non-metallic element that is a liquid at standard room temperature and pressure. It is a reddish-brown volatile liquid.

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.

How many chemical elements occur naturally on Earth rather than only by synthesis?

94 elements occur naturally, running from hydrogen up to plutonium, six of them only in extreme traces; every element beyond plutonium exists only because it was made in a reactor or accelerator.

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.

Gallium will melt in your hand; its melting point is roughly what temperature?

Gallium melts at 29.76 °C, roughly 30 °C, so body heat liquefies it; the value is so reproducible that gallium's melting point is a defining fixed point of the ITS-90 temperature scale.

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

Osmium, at about 22.6 g/cm³, is the densest naturally occurring element, twice lead's 11.3; its volatile, toxic tetroxide is used to stain biological samples for electron microscopy.

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 Mendeleev's eka-silicon predictions of fifteen years earlier 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?

Aes cyprium shortened to cuprum in Late Latin, which is where the symbol Cu comes from.

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

Sweden: Ytterby, a village on the island of Resarö near Stockholm, gave its name to yttrium, terbium, erbium and ytterbium, making it the only place on Earth to name four elements.

Uranium, neptunium and plutonium were named in sequence after what?

Pluto still counted as a planet when element 94 was named; its demotion came in 2006.

Europium and americium were both named after what?

Continents: europium (1901) honours Europe and americium (1944) the Americas; americium sits directly below europium in the table, so Seaborg's team named it by analogy.

Seaborgium and which other element were named after people still alive at the time?

Oganesson (element 118), named in 2016 for Yuri Oganessian, joined seaborgium (1997, for Glenn Seaborg) as the only elements named for people alive at the time; Oganessian was 83 when the name was approved.

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

Glenn Seaborg proposed in 1944 that elements from actinium onward form a second f-block series like the lanthanides; he co-discovered ten elements and shared the 1951 Nobel Prize in Chemistry with McMillan.

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 a German miners' word for which mythical being?

Goblin: German miners blamed a kobold for ore that looked valuable yet gave off poisonous arsenic fumes when smelted; Georg Brandt isolated cobalt from that ore in 1735.

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

Copper: Kupfernickel, 'copper-devil', was the miners' name for an arsenide 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 down roughly 1,500 gallons of it while hunting for the philosopher's stone and was left with a waxy 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-209, its only primordial isotope, was shown in 2003 to alpha-decay with a half-life of about 1.9 × 10¹⁹ years, roughly a billion times the age of the universe.

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

Astatine: less than a gram exists in the crust at any moment, all of it produced fleetingly by the decay of uranium and thorium; its longest-lived isotope, astatine-210, has a half-life of 8.1 hours.

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

Promethium, element 61, has no stable isotope; the longest-lived, promethium-145, lasts 17.7 years. It was named for the Titan who stole fire, symbolising 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: Vanadís, 'lady of the Vanir', is one of Freyja's names; Sefström chose it in 1830 for the element's beautifully coloured compounds, which del Río had found in 'brown lead' ore in 1801.

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

Nickel: iron, cobalt and nickel are the three elements ferromagnetic at room temperature; nickel's Curie temperature, above which it loses that magnetism, is about 355 °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: in 1884 the metal was precious enough to cap the Washington Monument with a 100-ounce pyramid; Hall and Héroult's electrolytic process, found independently in 1886, soon made it cheap.

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

Copenhagen: Coster and Hevesy identified hafnium there in 1922 by X-ray analysis of zirconium ores at Bohr's institute, decades after Mendeleev's table had predicted an element below zirconium.

Discovered in 1925, which element was the last stable one to be found?

Rhenium, found in 1925 by Noddack, Tacke and Berg and named after the Rhine, was the last stable element discovered; its boiling point of about 5,600 °C is among the highest of any 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 tantalite ore; Heinrich Rose chose the name in 1846.

Meitnerium was first synthesized in 1982 at the GSI laboratory near which German city?

Darmstadt: the GSI laboratory there made meitnerium in 1982 by firing iron-58 ions at bismuth-209; the name honouring Lise Meitner was approved in 1997, and its most stable isotope lasts only seconds.

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.

Who first ordered the elements by atomic weight on an 1862 spiral, the telluric helix?

Alexandre-Émile Béguyer de Chancourtois, a geologist, wrapped the elements by atomic weight around a cylinder in 1862; he named the 'telluric helix' for tellurium, which sat at its midpoint, and for the Earth.

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

Its symptoms are vague, so it stayed a favourite murder weapon until the Marsh test arrived in the 1830s.

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 in 1777 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: Vauquelin's 1798 name glucinium came from the Greek glykys, 'sweet', after the taste of beryllium salts, which are also highly toxic; the metal's stiffness later put it in 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.

How many elements are in period 6, which ties with period 7 for the most?

32: period 6 runs from caesium (55) to radon (86), the first row to include the 14 f-block lanthanides; period 7, francium to oganesson, also holds 32.

Which greenish-yellow gas did Humphry Davy establish as an element in 1810?

Chlorine: Scheele made the gas in 1774 but took it for an oxide of an unknown element; Davy showed in 1810 that it could not be decomposed and named it from the Greek chloros, 'pale green'.

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

Chalcogens, from the Greek for 'ore-formers', are group 16: oxygen, sulfur, selenium and tellurium, completed by the radioactive polonium and livermorium; most metal ores are oxides or sulfides.

Which element did Berzelius isolate in 1828 from a black Norwegian mineral?

Thorium: Berzelius extracted it in 1828 from a black mineral sent from Løvøya, Norway, naming both it and the mineral thorite after Thor; he had earlier misapplied the name to what proved to be yttrium phosphate.

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

Caesium: in 1967 the second was redefined as 9,192,631,770 periods of the radiation from caesium-133's hyperfine transition; the metal is also the softest solid element, with a Mohs hardness of 0.2.