Symbol: Hg

Atomic number: 80

Year discovered: Prehistoric; known since ancient times

Discovered by: Unknown

Additional information:

• The term mercurius was first employed about the 6th century by alchemists who used the symbol for the planet Mercury to represent the metal, which because of its mobile form and its color, was called quicksilver.
• Mercury was known to ancient Chinese and Hindus before 2000 B.C. and was found in tubes in Egyptian tombs dated from 1500 B.C.
• It is the only common metal that is liquid at ordinary temperatures.
• Mercury is a heavy, silvery-white metal; a rather poor conductor of heat, as compared with other metals, and a fair conductor of electricity.
• It easily forms alloys with many metals, such as gold, silver, and tin, and these alloys are called amalgams.
• Amalgams are used extensively in dentistry for fillings.
• Its ease in amalgamating with gold is made use of in the recovery of gold from its ores.
• The most important salts are mercuric chloride (corrosive sublimate—a violent poison), mercurous chloride (calomel, occasionally still used in medicine), mercury fulminate (a detonator used in explosives), and mercuric sulphide (vermillion, a high-grade paint pigment).
• Organic mercury compounds are important—and dangerous.
• Methyl mercury is a lethal pollutant found in rivers and lakes.
• The main source of pollution is industrial wastes settling to the river and lake bottoms.
• Mercury is a virulent poison and is readily absorbed through the respiratory tract, the gastrointestinal tract, or through unbroken skin.
• It acts as a cumulative poison since there are few pathways available to the body for its excretion.
• Since mercury is a very volatile element, dangerous levels are readily attained in air.
• Air saturated with mercury vapor at 20 degrees Centigrade contains a concentration that exceeds the toxic limit many times.
• The danger increases at higher temperatures; so It is therefore important that mercury be handled with care.
• Containers of mercury should be securely covered and spillage should be avoided.
• Mercury should only be handled in a well-ventilated area.
• If you are in possession of any mercury you are advised to take it to a properly qualified chemist for its safe disposal.
• The appearance of mercury is well known because of its use in many thermometers.
• It was common to demonstrate the formation of mercury in the laboratory by heating mercury sulphide, but this is strongly discouraged today because of the toxicity of mercury vapors.
• Despite its dangers, this method forms the basis of commercial extraction.
• Prepared cinnabar ore is heated in a current of air and the mercury vapor is condensed.
• In an article titled, “Mercury thermometers are falling out of favor” written by Traci Watson in the Thursday, April 1, 1999, issue of USA TODAY, the dangers of mercury were presented.
• Local and state officials in the U.S. are on a campaign to get people to switch to something else other than mercury thermometers.
• The bureaucrats say the ubiquitous device relies on one of the world’s most toxic elements, packaged in an easily shattered container.
• “Dangerous it may be, but the mercury thermometer is a wonderfully precise tool, thanks to mercury’s sensitivity to temperature and the fact that it doesn’t stick to glass.”
• Mercury was first used in a thermometer in 1714, but it took British physician Sir Thomas Allbutt to make the mercury thermometer a useful medical tool.
• “His 1866 invention of the modern clinical thermometer replaced a foot-long model that required 20 minutes to determine a patient’s temperature.”
• “Today’s thermometer contains only a smidgen of mercury, roughly 0.02 ounces.”
• Every year there are 5.7 million thermometers sold every year in the U.S. and Becton Dickinson, one of the largest makers of mercury thermometers, estimates that those thermometers could contribute as much as several tons of mercury to the environment every year.
• The problem is toxicity because mercury’s vapor is lethal when inhaled in concentrated amounts.
• Mercury can damage the nervous systems of people who eat large amounts of mercury-tainted fish and can lead to birth defects if pregnant women eat such fish.
• There are many ways for mercury to escape; such as, when a thermometer breaks, many people wash the spilled mercury down the drain and into the sewer system, from which it can get into water system.
• Throwing a mercury into the trash is a bad idea, too, because garbage may be incinerated, sending the mercury into the atmosphere; where it can fall with rain.
• Now, faced with mercury warnings about local fish poisoning and with high levels of mercury in wastewater plants, some U.S. officials are taking action by trying to replace mercury thermometers with digital models.

Name in other languages:

French: mercure

German: Quecksilber

Italian: mercurio

Spanish: mercurio

Back to the beginning of this list.

Symbol: Mo

Atomic number: 42

Year discovered: 1778

Discovered by: Karl Wilhelm Scheele (1742-1786), a Swedish chemist.

Additional information:

• In 1778, Karl Wilhelm Scheele conducted research on an ore now known as molybdenite.
• He concluded that it did not contain lead as was suspected at the time and reported that the mineral contained a new element that he called molybdenum after the mineral.
• Molybdenum metal was prepared in an impure form, in 1782, by Peter Jacob Hjelm (1746-1813), a Swedish mineralogist.
• Molybdenum is a silvery-white, hard, transition metal.
• It was often confused with graphite and lead ore.
• Molybdenum is used in alloys, electrodes, and catalysts.
• In World War II, a German artillery piece called “Big Bertha” contained molybdenum as an essential component of its steel.
• Molybdenum increases the strength, toughness, and uniformity of cast iron, in which it is extensively used.

Name in other languages:

French: molybdéne

German: Molybdän

Italian: molibdeno

Spanish: molibdeno

Back to the beginning of this list.

Symbol: Nd

Atomic number: 60

Year discovered: 1885

Discovered by: Carl Auer, Freiherr von Welsbach (1858-1929), an Austrian chemist.

Additional information:

• In 1885, von Welsbach separated didymium, an extract of cerite, into two new elemental components, neodymia and praseodymia, by repeated fractionation of ammonium didymium nitrate.
• While the free metal is a component of misch metal (a pyrophoric alloy for lighter flints), the element was not isolated in relatively pure form until 1925.
• It is slowly oxidized by air, burns easily to give sesquioxide and reacts gradually with cold water, or rapidly with hot water, to liberate hydrogen.
• Neodymium is one of the more reactive rare-earth metals and quickly tarnishes in air, forming an oxide that flakes, or chips, off and exposes the metal to further oxidation.
• The metal is used in the electronics industry, in the manufacture of steel and as a component of a number of alloys, among them the misch metal used in lighter flints (as mentioned earlier).
• Its compounds are used in the ceramics industry for glazes and to color glass.
• The crude oxide is employed for counteracting the color of iron in glass and the more pure compound is used in the production of the only known glass that is bright purple.
• A mixture of neodymium and praseodymium absorbs light in the region of the harmful sodium D lines and therefore is used in the glass of welders’ and glass blowers’ goggles.

Name in other languages:

French: néodyme

German: Neodym

Italian: neodimio

Spanish: neodimio

Back to the beginning of this list.

Symbol: Ne

Atomic number: 10

Year discovered: 1898

Discovered by: William Ramsay (1852-1916), British chemist, and Morris William Travers (1872-1961), British chemist.

Additional information:

• Neon was discovered by Sir William Ramsay and Morris Travers in 1898 very shortly after their discovery of the element krypton.
• Both elements were discovered through work on liquid air and a little later they discovered xenon using similar methods.
• Neon is a very inert element and it forms an unstable hydrate.
• In a vacuum discharge tube, neon glows reddish orange.
• Of all the rare gases, the discharge of neon is the most intense at ordinary voltages and currents.
• Liquid neon has over 40 times more refrigerating capacity than liquid helium and more than three times that of liquid hydrogen.
• Neon is used in a variety of lamps and other electrical devices that take advantage of its unusually high electrical conductivity and light-emissive power.
• Most gaseous conduction lamps and fluorescent lamps contain neon as a component of the gaseous mixture that carries electricity.
• Beginning in 1910, the French chemist Georges Claude (1870-1960) showed that electric discharges through the noble gases could be made to produce light.
• Most spectacular was the red light produced in this manner by neon, so that light produced this way by any gas came to be called “neon lights”.
• The fact that tubes filled with neon, or other gases, could be twisted into any shape (so that they spelled out words, for instance) made it inevitable that they would replace ordinary incandescent bulbs in advertising signs.

Name in other languages:

French: néon

German: Neon

Italian: neo

Spanish: neón

Back to the beginning of this list.

Symbol: Np

Atomic number: 93

Year discovered: 1940

Discovered by: Edwin M. McMillan (born 1907), American physicist, and Philip Hauge Abelson (born 1913) at the University of California in Berkeley.

Additional information:

• Neptunium was the first synthetic transuranium element of the actinide series.
• It was discovered by McMillan and Abelson in 1940 at Berkeley, California.
• They bombarded uranium with neutrons produced from a cyclotron.
• The metal is about as malleable as uranium made under the same conditions.

Name in other languages:

French: neptunium

German: Neptunium

Italian: nettunio

Spanish: neptunio

Back to the beginning of this list.

Symbol: Ni

Atomic number: 28

Year discovered: 1751

Discovered by: Baron Axel Fredrik Cronstedt (1722-1765), a Swedish mineralogist.

Additional information:

• Minerals containing nickel were of value for coloring glass green.
• The mineral used for coloring glass was called kupfernickel (false copper).
• Nickel was discovered by Baron Axel Frederik Cronstedt in a mineral called niccolite.
• Apparently, he had expected to extract copper from this mineral but he didn’t get any, obtaining instead a white metal that he called nickel after the mineral from which it was extracted.
• Cronstedt discovered that nickel, like iron but not as strongly, was attracted by a magnet.
• It was the first time that anything except iron had been found to be attracted by a magnet.
• In fact, magnets were eventually found to attract cobalt as well.
• An impure ore containing niccolite earlier than 1700 caused copper and silver miners in Saxony, Germany, considerable trouble because although it resembled copper in color, it yielded a brittle , unfamiliar product.
• They referred to it as “kupfernickel”, after “Old Nick” and his mischievous gnomes, and Cronstedt applied their name to his new element.
• His results were confirmed in 1775 by Torbern Olof Bergman (1735-1784), Swedish chemist and physicist, and the name nickel soon became generally accepted.
• About a century passed before nickel was mined in quantity for a growing world market.

Name in other languages:

French: nickel

German: Nickel

Italian: nichel

Spanish: niquel

Back to the beginning of this list.

Symbol: Nb

Atomic number: 41

Year discovered: 1801

Discovered by: Charles Hachett (1765-1847), a British chemist.

Additional information:

• Niobium was discovered, in 1801, by Charles Hatchett in an ore called columbite sent to England more than a century before by John Winthrop, the Younger, the first governor of Connecticut, USA.
• The mineral was found in the British Museum.
• Hatchett called the new element “columbium” in honor of the United States, which was sometimes known by the name “Columbia”.
• He was not able to isolate the free element.
• There was then some confusion concerning tantalum and niobium which was resolved by German chemist, Heinrich Rose, who named niobium, and by Marignac in 1846.
• The name “niobium” is now preferred as the official nomenclature replacing the original name “columbium” and so the United States lost the honor.
• The metal niobium was first prepared, in 1864, by Blomstrand, who reduced chloride by heating it in a hydrogen atmosphere.
• The name niobium was adopted by IUPAC (International Union of Pure and Applied Chemistry) in 1950, but a few commercial producers still refer to it as “columbium”.
• Niobium is a shiny, white, soft, and ductile metal, and takes on a bluish cast when exposed to air at room temperatures for a long time.
• The metal starts to oxidize in air at elevated temperatures, and when processed at even moderate temperatures must be placed in a protective atmosphere.

Name in other languages:

French: niobium

German: Niob

Italian: niobio

Spanish: niobio

Back to the beginning of this list.

Symbol: N

Atomic number: 7

Year discovered: 1772

Discovered by: Daniel Rutherford (1749-1819), a British chemist.

Additional information:

• It was known during the 18th century that air contains at least two gases, one of which supports combustion and life and another which does not.
• Nitrogen was discovered by Daniel Rutherford, in 1772, who called it noxious air, but Scheele, Cavendish, Priestley, and others at about the same time studied “burnt” or “dephlogisticated” air, as air without oxygen was then called.
• Common air is a mixture of two gases, which C. W. Scheele called “foul air” (nitrogen) and “fire air” (oxygen).
• Nitrogen makes up about 78% of the atmosphere by volume.
• Nitrogen can be obtained by liquefaction and fractional distillation from air.
• The element seemed so inert that Lavoisier named it “azote”, meaning “without life”; however, its compounds are vital components of foods, fertilizers, and explosives.
• Nitrogen gas is colorless, odorless, and generally inert.
• The name nitrogen was introduced by J. A. C. Chaptal (1790) to indicate that the element is a constituent of nitre (potassium nitrate, or saltpeter).
• As a liquid it is also colorless and odorless, and is similar in appearance to water.
• When nitrogen is heated, it combines directly with magnesium, lithium, or calcium.
• When mixed with oxygen and subjected to electric sparks, it forms nitric oxide and then dioxide.
• Nitrogen is “fixed” from the atmosphere by bacteria in the roots of certain plants such as clover and legumes. Hence the usefulness of clover and beans, etc. in crop rotation is vital.

Name in other languages:

French: azote

German: Stickstoff

Italian: azoto

Spanish: nitrógeno

Back to the beginning of this list.

Symbol: No

Atomic number: 102

Year discovered: 1958

Discovered by: Albert Ghiorso (born July 15, 1915), Torbjorn Sikkeland, J. R. Walton, and Glenn Theodore Seaborg (1912-1999), American physicist, on the basis of an experiment performed at the University of California, Berkeley.

Additional information:

• A team working in Stockholm reported, in 1957, an isotope whose atomic number is 102. They named the element nobelium after Alfred Nobel.
• In 1958, a group at Berkeley, California, reported that they were unable to reproduce this work, findings agreed to by a Russian group at Dubna.
• An authenticated discovery of nobelium was made in 1958 by Seaborg and others at Berkeley, California.
• Nobelium is a radioactive “rare earth metal” named for Alfred Nobel who discovered dynamite.

Name in other languages:

French: nobélium

German: Nobelium

Italian: nobelio

Spanish: nobelio

Back to the beginning of this list.

Symbol: Os

Atomic number: 76

Year discovered: 1803

Discovered by: Smithson Tennant (1761-1815), a British chemist.

Additional information:

• Osmium was discovered, in 1803, by Smithson Tennant in the dark colored residue left when crude platinum was dissolved by aqua regia (a mixture of hydrochloric and nitric acid).
• This dark residue contains both osmium and iridium.
• Osmium metal is lustrous, bluish white, extremely hard, and brittle even at high temperatures.
• It has the highest melting point and lowest vapor pressure of the platinum group.
• The solid metal is not affected by air at room temperature, but the powdered or spongy metal slowly gives off osmium tetroxide, which is a powerful oxidizing agent and has a strong odor.
• Tetroxide is highly toxic and concentrations in air can cause lung congestion, skin damage, or eye damage.
• The industrial extraction of osmium is complex as the metal occurs in ores mixed with other metals such as ruthenium, rhodium, palladium, silver, platinum, and gold.
• Sometimes extraction of the precious metals such as iridium, rhodium, platinum and palladium is the main focus of a particular industrial operation while in other cases it is a by-product.
• The extraction is complex because of the presence of other metals and is only worthwhile because osmium is useful as a specialist metal and is the basis of some catalysts in industries.
• Because wires of the metal can be heated to high temperatures, they were used as filaments in early incandescent lamps; however, osmium was replaced by tungsten for this purpose.
• A hard alloy of osmium and iridium is used commercially for tips of fountain pens and phonograph needles.

Name in other languages:

French: osmium

German: Osmium

Italian: osmio

Spanish: osmio

Back to the beginning of this list.

Symbol: O

Atomic number: 8

Year discovered: 1772 (by Scheele) and in 1774 (by Priestley).

Discovered by: Karl Wilhelm Scheele (1742-1786), a Swedish chemist, and Joseph Priestley (1733-1804), an English chemist.

Additional information:

• Leonardo da Vinci suggested that air consists of at least two different gases.
• Previously air was thought to be an element in its own right.
• He was also aware that one of these gases supported both flames and life.
• Oxygen was prepared by several workers before 1772, but these workers did not recognize it as an element.
• Joseph Priestley is generally credited with its discovery (who made oxygen by heating lead or mercury oxides), but Carl Wilhelm Scheele also reported it independently.
• Mercury, when heated in air, will form a brick-red compound, which we now call “mercuric oxide”.
• Priestley heated some of this compound in a test-tube by using a lens to concentrate sunlight upon it.
• When he did this, the compound broke up, liberating mercury, which appeared as shining globules in the upper portion of the test-tube.
• In addition, a gas was given off that possessed most unusual properties.
• Combustibles burned more brilliantly and rapidly in it than they did in ordinary air.
• Mice placed in an atmosphere of this gas were particularly frisky, and Priestley himself felt “light and easy” when he breathed it.
• When French chemist Antoine-Laurent Lavoisier (1743-1794) heard of the experiments of Priestley and British chemist Daniel Rutherford (who discovered a new gas that eventually came to be called “nitrogen”); he realized in the light of his own experiments that air must consist of a mixture of two gases.
• One-fifth was Priestley’s gas, which Lavoisier named oxygen (from the Greek words meaning “acid producer”, because it was mistakenly felt at the time that all acids contained oxygen).
• Four-fifths were Rutherfords’ gas, which Lavoisier named “azote” (from Greek words meaning “no life”), but which later came to be known as nitrogen.
• It seemed obvious that it was oxygen that supported combustion and animal life and oxygen that was involved in rusting.
• Animals must consume oxygen and produce carbon dioxide, and from Priestley’s earlier experiment, plants must consume carbon dioxide and produce oxygen.
• In a classic case of scientific misfortune, the Swedish chemist Carl Wilhelm Scheele had discovered oxygen at least two years before Priestley did, and by the same method.
• Why didn’t Scheele get the credit for the discovery? Because it wasn’t published (through the negligence of a publisher) until after Priestley’s discovery had been reported, so Priestley got the credit.
• With these two forms of life, the atmosphere tends to maintain a stability and balance.
• The discovery that air, invisible air, was “something” and not “nothing” profoundly altered how all scientists thought.
• Joseph Priestly is quoted as saying, “We cannot solve one doubt without creating several new ones.”
• The behavior of oxygen and nitrogen as components of air led to the advancement of the phlogiston theory of combustion, which influenced chemists for a century or so, and which delayed an understanding of the nature of air for many years.
• Phologiston is a hypothetical substance formerly thought to be a volatile constituent of all combustible substances released as flame in combustion.

Name in other languages:

French: oxygène

German: Sauerstoff

Italian: ossigeno

Spanish: oxígeno

Back to the beginning of this list.

Symbol: Pd

Atomic number: 46

Year discovered: 1803

Discovered by: William Hyde Wollaston (1766-1828), a British chemist.

Additional information:

• William Hyde Wollaston discovered palladium in 1803-4 in crude platinum ore from South America.
• He dissolved the ore in aqua regia (a mixture of hydrochloric and nitric acids), neutralized the acid with sodium hydroxide, and precipitated the platinum by treatment with ammonium chloride, as ammonium chloroplatinate.
• Palladium was then removed as palladium cyanide by treatment with mercuric cyanide. The metal was produced from this cyanide by heating.
• As a metal, palladium is ductile and easily worked.
• It is not tarnished by the atmosphere at ordinary temperatures; consequently, the metal and its alloys serve as substitutes for platinum in jewelry and in electrical contacts, and the beaten leaf is used for decorative purposes.
• Palladium is useful for the preparation of dental alloys.
• Since it is much lighter than platinum, palladium has been used for the construction of astronomical and other fine instruments.
• Relatively small amounts of paladium alloyed with gold yield “white gold”.

Name in other languages:

French: palladium

German: Palladium

Italian: palladio

Spanish: paladio

Back to the beginning of this list.

Symbol: P

Atomic number: 15

Year discovered: 1669

Discovered by: Hennig Brand (died ca. 1692), an alchemist from Hamburg, Germany.

Additional information:

• Of the substances chemists now consider to be elements, nine were known to the ancients.
• These included seven metals: gold, silver, copper, tin, iron, lead, and mercury; and two nonmetals: carbon and sulfur.
• Four more elements were probably known and were unmistakably described by the medieval alchemists: arsenic, antimony, bismuth, and zinc.
• No one knows who first discovered any of these elements, nor when.
• The situation changed when the German alchemist, Hennig Brand, began to search for something that would enable him to create gold; and for some reason, he thought he would find it in urine.
• He did not find gold, but he did come up with a white waxy substance that glowed faintly in the air.
• All of the elements discovered after 1669 can be attributed to a specific person and a specific time and Brand’s discovery of phosphorus is the first of which this can be said. [Asimov’s Chronology of Science and Discovery by Isaac Asimov]
• As stated earlier, phosphorus was discovered in 1669 by Hennig Brand, who prepared it from the residue of evaporated urine.
• No less than 50-60 buckets were used per experiment, each of which required more than two weeks to complete.
• News of the discovery soon spread around Germany.
• At first, Brand didn’t disclose his method of producing phosphorus.
• First, he sold the secret to Johann Kraft of Dresden, Germany.
• The chemist Johann Kunckel tried to learn the secret process from Brand, but he could only find that urine had been used as the source of the phosphorus.
• With this information, Kunckel was finally able, after many trials, to duplicate Brand’s accomplishment.
• Kunckel also attempted to keep the process a secret and, like Brand and Kraft, tried at various times to sell details of the process.
• Gottfried Leibniz, the German mathematician, then the librarian for Duke Johann Friedrich at Hanover, arranged a contract between Brand and the duke, under which Brand was to demonstrate his process and reveal his method.
• It is easy to understand the widespread interest that was aroused in the 17th century by the discovery of such a remarkable substance as phosphorus.
• A substance that glowed in the dark and flamed spontaneously when exposed to air was something startlingly new and mysterious.
• It is unusual that an element so difficult to isolate should have been discovered through the unguided fumbling of an alchemist.
• In the decades that followed 1680, methods for the preparation of phosphorus from various animal and vegetable materials were developed and, in some cases, published.
• It was not until 1775, more than a hundred years after Brand’s discovery, that Carl Scheele published the much easier method of preparing the element from bones, which then became the chief raw material used as a source of phophorus.
• Phosphorus is essential for both animal and vegetable life.
• Man gets the phosphorus needed from compounds in the vegetables eaten.
• Plants get it from the soil, principally from phosphates.
• Phosphate is present in rocks and in the remains of organisms.
• Phosphates are necessary to the growth of organisms and have extensive use in fertilizers.
• Bread contains phosphates.

Name in other languages:

French: phosphore

German: Phosphor

Italian: fosforo

Spanish: fósforo

Back to the beginning of this list.

Symbol: Pt

Atomic number: 78

Year discovered: 1748

Discovered by: Antonio de Ulloa (1716-1795), a Spanish naval officer and scientist, in South America.

Additional information:

• A metallic casket found among the relics of seventh century B.C. Egypt is reported to be of platinum.
• The metal was used by pre-Columbian Indians but platinum was “rediscovered” in South America by a Spanish scientist, Antonio de Ulloa in 1748.
• He remarked about its peculiar properties, and when properly examined, it turned out to be denser than gold, higher-melting, and even less reactive; which proved to be very useful to scientists for just these properties.
• In 1822, amounts of platinum were discovered in the Ural Mountains in Russia.
• The usefulness of platinum is due to its resistance to corrosion or chemical attack and to its high melting point.
• With such a high melting point platinum is not easily fused or cast.
• Platinum did not receive general recognition in ancient times.
• Large deposits as heavy river sands were uncovered in the 16th-century Spanish conquest of South America.
• The Spaniard called the new metal “Platina del Pinto” after the Rio Pinto, from which its present name was taken and “platina” is also supposed to be a Spanish word for “silver”.
• Samples of the element received the general attention of European scientists in the latter 18th century.
• Platinum occurs in native alloys which frequently contain smaller amounts of other platinum metals.
• Platinum is used in the preparation of electrical contacts, and spark-plug points, because it resists the high temperature and chemical attack of electric arcs.
• The manufacture of jewelry and dental alloys consumes large amounts of the metal.

Name in other languages:

French: platine

German: Platin

Italian: platino

Spanish: platino

Back to the beginning of this list.