We all know about the Elements of the Periodic Table, but which elements are there? Which grouping do they belong to? Our short (ish) guide to all of the elements in the periodic table will tell you a little bit about each element.
Reactive Non-Metals
Non-metals are elements that form negative ions by accepting or gaining electrons. Non-metals usually have 4, 5, 6 or 7 electrons in their outermost shell.
Non-metals are those which lack all the metallic attributes. They are good insulators of heat and electricity. They are mostly gases and sometimes liquid. Some are even solid at room temperatures like Carbon, sulfur, and phosphorus.
Hydrogen is the chemical element with the symbol H and atomic number 1. With a standard atomic weight of 1.008, hydrogen is the lightest element in the periodic table. Hydrogen is the most abundant chemical substance in the Universe, constituting roughly 75% of all baryonic mass.
Carbon (from Latin: carbo “coal”) is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent-making four electrons available to form covalent chemical bonds. Carbon is one of the few elements known since antiquity. It is the second most abundant element in the human body by mass (about 18.5%) after oxygen.
Nitrogen is the chemical element with the symbol N and atomic number 7. It was first discovered and isolated by Scottish physician Daniel Rutherford in 1772. Although Carl Wilhelm Scheele and Henry Cavendish had independently done so at about the same time, Rutherford is generally accorded the credit because his work was published first. Nitrogen makes up 78% of our air.
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds.
Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. As the most electronegative element, it is extremely reactive, as it reacts with almost all other elements, except for argon, neon, and helium.
Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus, and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Earth.
Sulfur is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent, and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula S8. Elemental sulfur is a bright yellow, crystalline solid at room temperature. Sulfur was known in ancient times, being mentioned for its uses in ancient Greece, China, and Egypt.
Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them.
Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, and also has similarities to arsenic.
Bromine is a chemical element with symbol Br and atomic number 35. It is the third-lightest halogen, and is a fuming red-brown liquid at room temperature that evaporates readily to form a similarly colored gas. Its properties are thus intermediate between those of chlorine and iodine.
Iodine is a chemical element with the symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a lustrous, purple-black non-metallic solid at standard conditions. The element was discovered by the French chemist Bernard Courtois in 1811. It was named two years later by Joseph Louis Gay-Lussac, after the Greek ἰώδης “violet-colored”.
Alkali Metals
The alkali metals, found in group 1 of the periodic table (formerly known as group IA), are very reactive metals that do not occur freely in nature. These metals have only one electron in their outer shell. Therefore, they are ready to lose that one electron in ionic bonding with other elements. As with all metals, the alkali metals are malleable, ductile, and are good conductors of heat and electricity. The alkali metals are softer than most other metals. Cesium and francium are the most reactive elements in this group. Alkali metals can explode if they are exposed to water.
Lithium (from Greek: λίθος, romanized: lithos, lit. ‘stone’) is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the lightest metal and the lightest solid element.
Sodium is a chemical element with the symbol Na (from Latin natrium) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table, because it has a single electron in its outer shell, which it readily donates, creating a positively charged ion—the Na+ cation. Sodium is the sixth most abundant element in the Earth’s crust and exists in numerous minerals such as feldspars, sodalite, and rock salt (NaCl).
Sodium was first isolated by Humphry Davy in 1807 by the electrolysis of sodium hydroxide.
Potassium is a chemical element with the symbol K (from Neo-Latin kalium) and atomic number 19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmospheric oxygen to form flaky white potassium peroxide in only seconds of exposure. It was first isolated from potash, the ashes of plants, from which its name derives.
Rubidium is a chemical element with the symbol Rb and atomic number 37. Rubidium is a very soft, silvery-white metal in the alkali metal group. Rubidium metal shares similarities to potassium metal and cesium metal in physical appearance, softness and conductivity.
Cesium is a chemical element with the symbol Cs and atomic number 55. It is a soft, silvery-golden alkali metal with a melting point of 28.5 °C (83.3 °F), which makes it one of only five elemental metals that are liquid at or near room temperature.
Francium is a chemical element with the symbol Fr and atomic number 87. Prior to its discovery, it was referred to as eka-cesium. It is extremely radioactive; its most stable isotope, francium-223 has a half-life of only 22 minutes. It is the second-most electropositive element, behind only caesium, and is the second rarest naturally occurring element (after astatine).
Alkaline Earth Metals
The elements in group one of the periodic table (with the exception of hydrogen) are known as the alkali metals because they form alkaline solutions when they react with water. Each of these elements has just one valence electron, which means that they form only weak metallic bonds. As a result, they are relatively soft and have low melting points. Alkali metals also readily combine with the elements of group seventeen (chlorine, fluorine, bromine, etc.) to form stable ionic compounds like sodium chloride.
Beryllium is a chemical element with the symbol Be and atomic number 4. It is a relatively rare element in the universe, usually occurring as a product of the spallation of larger atomic nuclei that have collided with cosmic rays.
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray solid which bears a close physical resemblance to the other five elements in the second column (group 2, or alkaline earth metals) of the periodic table. Magnesium is the ninth most abundant element in the universe.
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologs strontium and barium. It is the fifth most abundant element in Earth’s crust and the third most abundant metal, after iron and aluminum.
Strontium is the chemical element with the symbol Sr and atomic number 38. An alkaline earth metal, strontium is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is exposed to air. Strontium has physical and chemical properties similar to those of its two vertical neighbors in the periodic table, calcium, and barium.
Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element. Its hydroxide, known in pre-modern times as baryta, does not occur as a mineral, but can be prepared by heating barium carbonate.
Radium is a chemical element with the symbol Ra and atomic number 88. It is the sixth element in group 2 of the periodic table, also known as the alkaline earth metals. Pure radium is silvery-white, but it readily reacts with nitrogen (rather than oxygen) on exposure to air, forming a black surface layer of radium nitride.
Transition Metals
The most striking similarities shared by the 24 elements in question are that they are all metals and that most of them are hard, strong, and lustrous, have high melting and boiling points and are good conductors of heat and electricity. The range in these properties is considerable; therefore the statements are comparative with the general properties of all the other elements.
Scandium is a chemical element with the symbol Sc and atomic number 21. A silvery-white metallic d-block element, it has historically been classified as a rare-earth element, together with yttrium and the lanthanides. It was discovered in 1879 by spectral analysis of the minerals euxenite and gadolinite from Scandinavia.
Yttrium is a chemical element with the symbol Y and atomic number 39. It is a silvery-metallic transition metal chemically similar to the lanthanides and has often been classified as a “rare-earth element”.
Titanium is a chemical element with the symbol Ti and atomic number 22. It is a lustrous transition metal with a silver color, low density, and high strength. Titanium is resistant to corrosion in sea water, aqua regia, and chlorine. Titanium was discovered in Cornwall, Great Britain, by William Gregor in 1791 and was named by Martin Heinrich Klaproth after the Titans of Greek mythology.
Zirconium is a chemical element with the symbol Zr and atomic number 40. The name zirconium is taken from the name of the mineral zircon. It is a lustrous, grey-white, strong transition metal that closely resembles hafnium and, to a lesser extent, titanium. Zirconium is mainly used as a refractory and opacifier, although small amounts are used as an alloying agent for its strong resistance to corrosion.
Hafnium is a chemical element with the symbol Hf and atomic number 72. A lustrous, silvery gray, tetravalent transition metal, hafnium chemically resembles zirconium and is found in many zirconium minerals. Its existence was predicted by Dmitri Mendeleev in 1869, though it was not identified until 1923, by Coster and Hevesy, making it the last stable element to be discovered.
Rutherfordium is a synthetic chemical element with the symbol Rf and atomic number 104, named after New Zealand physicist Ernest Rutherford. As a synthetic element, it is not found in nature and can only be created in a laboratory. It is radioactive; the most stable known isotope, 267Rf, has a half-life of approximately 1.3 hours.
Vanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery-grey, malleable transition metal. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an oxide layer (passivation) somewhat stabilizes the free metal against further oxidation.
Niobium, formerly known as columbium, is a chemical element with the symbol Nb (formerly Cb) and atomic number 41. Niobium is a light grey, crystalline, and ductile transition metal. Pure niobium has a hardness similar to that of pure titanium and it has similar ductility to iron. Niobium oxidizes in the earth’s atmosphere very slowly, hence its application in jewelry as a hypoallergenic alternative to nickel.
Tantalum is a chemical element with the symbol Ta and atomic number 73. Previously known as tantalum, it is named after Tantalus, a villain from Greek mythology. Tantalum is a rare, hard, blue-gray, lustrous transition metal that is highly corrosion-resistant.
Dubnium is a synthetic chemical element with the symbol Db and atomic number 105. Dubnium is highly radioactive: the most stable known isotope, dubnium-268, has a half-life of about 28 hours. This greatly limits the extent of research on dubnium.
Chromium is a chemical element with the symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard and brittle transition metal. Chromium is the main additive in stainless steel, to which it adds anti-corrosive properties. Chromium is also highly valued as a metal that is able to be highly polished while resisting tarnishing. Polished chromium reflects almost 70% of the visible spectrum.
Molybdenum is a chemical element with the symbol Mo and atomic number 42. Molybdenum minerals have been known throughout history, but the element was discovered (in the sense of differentiating it as a new entity from the mineral salts of other metals) in 1778 by Carl Wilhelm Scheele. The metal was first isolated in 1781 by Peter Jacob Hjelm.
Tungsten, or wolfram, is a chemical element with the symbol W and atomic number 74. The name tungsten comes from the former Swedish name for the tungstate mineral scheelite, tung sten or “heavy stone”. Tungsten is a rare metal found naturally on Earth almost exclusively combined with other elements in chemical compounds rather than alone.
Seaborgium is a synthetic chemical element with the symbol Sg and atomic number 106. It is named after the American nuclear chemist Glenn T. Seaborg. As a synthetic element, it can be created in a laboratory but is not found in nature. It is also radioactive; the most stable known isotope, 269Sg, has a half-life of approximately 14 minutes.
Manganese is a chemical element with the symbol Mn and atomic number 25. It is not found as a free element in nature; it is often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy uses, particularly in stainless steel.
Technetium is a chemical element with the symbol Tc and atomic number 43. It is the lightest element whose isotopes are all radioactive. Nearly all technetium is produced as a synthetic element, and only about 18,000 tons are estimated to exist at any given time in the Earth’s crust.
Rhenium is a chemical element with the symbol Re and atomic number 75. It is a silvery-gray, heavy transition metal. With an estimated average concentration of 1 part per billion (ppb), rhenium is one of the rarest elements in the Earth’s crust.
Bohrium is a synthetic chemical element with the symbol Bh and atomic number 107. It is named after Danish physicist Niels Bohr. As a synthetic element, it can be created in a laboratory but is not found in nature. All known isotopes of bohrium are extremely radioactive; the most stable known isotope is 270Bh with a half-life of approximately 61 seconds, though the unconfirmed 278Bh may have a longer half-life of about 690 seconds.
Iron is a chemical element with symbol Fe (from Latin: Ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is by mass the most common element on Earth, forming much of Earth’s outer and inner core. It is the fourth most common element in the Earth’s crust. Humans started to master that process in Eurasia only about 2000 BCE, and the use of iron tools and weapons began to displace copper alloys, in some regions, only around 1200 BCE. That event is considered the transition from the Bronze Age to the Iron Age. In the modern world, iron alloys, such as steel, inox, cast iron, and special steels are by far the most common industrial metals, because of their high mechanical properties and low cost.
Ruthenium is a chemical element with the symbol Ru and atomic number 44. It is a rare transition metal belonging to the platinum group of the periodic table. Like the other metals of the platinum group, ruthenium is inert to most other chemicals. Russian-born scientist of Baltic-German ancestry Karl Ernst Claus discovered the element in 1844 at Kazan State University and named ruthenium in honor of Russia (Ruthenia is the Latin name of Russia).
Osmium (from Greek ὀσμή osme, “smell”) is a chemical element with the symbol Os and atomic number 76. It is a hard, brittle, bluish-white transition metal in the platinum group that is found as a trace element in alloys, mostly in platinum ores. Osmium is the densest naturally occurring element, with an experimentally measured (using x-ray crystallography) density of 22.59 g/cm3.
Hassium is a chemical element with the symbol Hs and atomic number 108. It is not known to occur in nature and has been made only in laboratories in minuscule quantities. Hassium is highly radioactive; the most stable known isotope, 269Hs, has a half-life of approximately 16 seconds.
Cobalt is a chemical element with the symbol Co and atomic number 27. Like nickel, cobalt is found in the Earth’s crust only in chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal.
Rhodium is a chemical element with the symbol Rh and atomic number 45. It is a rare, silvery-white, hard, corrosion-resistant, and chemically inert transition metal. It is a noble metal and a member of the platinum group. Naturally-occurring rhodium is usually found as free metal, as an alloy with similar metals, and rarely as a chemical compound in minerals such as bowieite and rhodplumsite. It is one of the rarest and most valuable precious metals.
Iridium is a chemical element with the symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum group, iridium is the second-densest metal (after osmium) with a density of 22.56 g/cm3 as defined by experimental X-ray crystallography.
Nickel is a chemical element with the symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is hard and ductile. Even pure native nickel is found in Earth’s crust only in tiny amounts, usually in ultramafic rocks, and in the interiors of larger nickel-iron meteorites that were not exposed to oxygen when outside Earth’s atmosphere.
Palladium is a chemical element with the symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired by her when she slew Pallas.
Platinum is a chemical element with the symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Its name is derived from the Spanish term platino, meaning “little silver”.
Copper is a chemical element with the symbol Cu (from Latin: cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange color. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys.
Silver is a chemical element with the symbol Ag (from the Latin argentum, derived from the Proto-Indo-European h₂erǵ: “shiny” or “white”) and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. The metal is found in the Earth’s crust in the pure, free elemental form (“native silver”), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a by-product of copper, gold, lead, and zinc refining.
Gold is a chemical element with the symbol Au (from Latin: aurum) and atomic number 79, making it one of the highest atomic number elements that occur naturally. In its purest form, it is a bright, slightly reddish yellow, dense, soft, malleable, and ductile metal.
Lanthanide
Lanthanoids are metals that are related to each other in how they behave. Most of them slowly turn into their hydroxides when they are placed into water, like the alkali metals. They usually form a coating of oxide when placed in the air, like most metals. Lanthanides, with Scandium and Yttrium, are called rare earth elements. All the lanthanoids are silvery-white soft metals and tarnish rapidly in air. The hardness increases with increasing atomic number.
Lanthanides are not abundant, and only small amounts are mined. Some have various uses in magnets, superconductors, chemical catalysts, and optical equipment such as lasers.
Lanthanum is a chemical element with the symbol La and atomic number 57. It is a soft, ductile, silvery-white metal that tarnishes slowly when exposed to air and is soft enough to be cut with a knife. Lanthanum has no biological role in humans but is essential to some bacteria.
Cerium is a chemical element with the symbol Ce and atomic number 58. Cerium is a soft, ductile and silvery-white metal that tarnishes when exposed to air. Cerium is the second element in the lanthanide series. It is also considered one of the rare-earth elements.
Praseodymium is a chemical element with the symbol Pr and atomic number 59. It is the third member of the lanthanide series and is traditionally considered to be one of the rare-earth metals. Praseodymium is a soft, silvery, malleable and ductile metal, valued for its magnetic, electrical, chemical, and optical properties.
Neodymium is a chemical element with the symbol Nd and atomic number 60. Neodymium belongs to the lanthanide series and is a rare-earth element. It is a hard, slightly malleable silvery metal that quickly tarnishes in air and moisture. It is alloyed to make powerful magnets.
Promethium is a chemical element with the symbol Pm and atomic number 61. All of its isotopes are radioactive; it is extremely rare, with only about 500–600 grams naturally occurring in Earth’s crust at any given time.
Samarium is a chemical element with the symbol Sm and atomic number 62. It is a moderately hard silvery metal that slowly oxidizes in air. Samarium has no significant biological role but is only slightly toxic.
Europium is a chemical element with the symbol Eu and atomic number 63. Europium is the most reactive lanthanide by far, having to be stored under an inert fluid to protect it from atmospheric oxygen or moisture. Europium is also the softest lanthanide, as it can be dented with a fingernail and easily cut with a knife. Europium is one of the rarest of the rare earth elements on Earth.
Gadolinium is a chemical element with the symbol Gd and atomic number 64. Gadolinium is a silvery-white metal when oxidation is removed. It is only slightly malleable and is a ductile rare-earth element.
Terbium is a chemical element with the symbol Tb and atomic number 65. It is a silvery-white, rare earth metal that is malleable, ductile, and soft enough to be cut with a knife.
Dysprosium is a chemical element with the symbol Dy and atomic number 66. It is a rare earth element with a metallic silver luster. Dysprosium is never found in nature as a free element, though it is found in various minerals, such as xenotime.
Holmium is a chemical element with the symbol Ho and atomic number 67. Part of the lanthanide series, holmium is a rare-earth element. Holmium was discovered by Swedish chemist Per Theodor Cleve. Its oxide was first isolated from rare-earth ores in 1878.
Erbium is a chemical element with the symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements. It is a lanthanide, a rare earth element, originally found in the gadolinite mine in Ytterby in Sweden, from which it got its name.
Thulium is a chemical element with the symbol Tm and atomic number 69. It is the thirteenth and third-last elements in the lanthanide series. In aqueous solution, like compounds of other late lanthanides, soluble thulium compounds form coordination complexes with nine water molecules.
Ytterbium is a chemical element with the symbol Yb and atomic number 70. It is the fourteenth and penultimate element in the lanthanide series. Because of its closed-shell electron configuration, its density and melting and boiling points differ significantly from those of most other lanthanides.
Lutetium is a chemical element with the symbol Lu and atomic number 71. It is a silvery-white metal, which resists corrosion in dry air, but not in moist air. Lutetium is the last element in the lanthanide series, and it is traditionally counted among the rare earths.
Metalloids
A metalloid is a chemical element that exhibits some properties of metals and some of the nonmetals. In the periodic table, metalloids form a jagged zone dividing elements that have clear metallic properties from elements that have clear nonmetallic properties.
Boron is a chemical element with the symbol B and atomic number 5. Produced entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, it is a low-abundance element in the Solar system and in the Earth’s crust.
Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard and brittle crystalline solid with a blue-grey metallic lustre; and it is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, and lead are below it. It is relatively unreactive.
Germanium is a chemical element with the symbol Ge and atomic number 32. It is a lustrous, hard-brittle, grayish-white metalloid in the carbon group, chemically similar to its group neighbors silicon and tin. Pure germanium is a semiconductor with an appearance similar to elemental silicon. Like silicon, germanium naturally reacts and forms complexes with oxygen in nature.
Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but only the gray form, which has a metallic appearance, is important to industry.
Antimony is a chemical element with the symbol Sb (from Latin: stibium) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite. Antimony compounds have been known since ancient times and were powdered for use as medicine and cosmetics, often known by the Arabic name, kohl.
Tellurium is a chemical element with the symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. Tellurium is far more common in the Universe as a whole than on Earth.
Astatine is a radioactive chemical element with the symbol At and atomic number 85. It is the rarest naturally occurring element in the Earth’s crust, occurring only as the decay product of various heavier elements.
Actinide
All actinides are radioactive and release energy upon radioactive decay; naturally occurring uranium and thorium, and synthetically produced plutonium is the most abundant actinides on Earth. These are used in nuclear reactors and nuclear weapons. Uranium and thorium also have diverse current or historical uses, and americium is used in the ionization chambers of most modern smoke detectors.
Actinium is a chemical element with the symbol Ac and atomic number 89. It was first isolated by French chemist André-Louis Debierne in 1899. Friedrich Oskar Giesel later independently isolated it in 1902 and, unaware that it was already known, gave it the name emanium.
Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. Thorium is silvery and tarnishes black when it is exposed to air, forming thorium dioxide; it is moderately hard, malleable, and has a high melting point.
Protactinium (formerly protoactinium) is a chemical element with the symbol Pa and atomic number 91. It is a dense, silvery-gray actinide metal that readily reacts with oxygen, water vapor, and inorganic acids. Because of its scarcity, high radioactivity, and high toxicity, there are currently no uses for protactinium outside scientific research, and for this purpose, protactinium is mostly extracted from spent nuclear fuel.
Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weakly radioactive because all isotopes of uranium are unstable; the half-lives of its naturally occurring isotopes range between 159,200 years and 4.5 billion years. Its density is about 70% higher than that of lead and slightly lower than that of gold or tungsten.
Neptunium is a chemical element with the symbol Np and atomic number 93. A radioactive actinide metal, neptunium is the first transuranic element. Its position in the periodic table just after uranium, named after the planet Uranus, led to it being named after Neptune, the next planet beyond Uranus.
Plutonium is a radioactive chemical element with the symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air and forms a dull coating when oxidized. The element normally exhibits six allotropes and four oxidation states.
Americium is a synthetic radioactive chemical element with the symbol Am and atomic number 95. It is a transuranic member of the actinide series, in the periodic table located under the lanthanide element europium, and thus by analogy was named after the Americas.
Curium is a transuranic radioactive chemical element with the symbol Cm and atomic number 96. This element of the actinide series was named after Marie and Pierre Curie – both were known for their research on radioactivity.
Berkelium is a transuranic radioactive chemical element with the symbol Bk and atomic number 97. It is a member of the actinide and transuranium element series. It is named after the city of Berkeley, California, the location of the Lawrence Berkeley National Laboratory (then the University of California Radiation Laboratory) where it was discovered in December 1949. Berkelium was the fifth transuranium element discovered after neptunium, plutonium, curium, and americium.
Californium is a radioactive chemical element with the symbol Cf and atomic number 98. The element was first synthesized in 1950 at the Lawrence Berkeley National Laboratory (then the University of California Radiation Laboratory), by bombarding curium with alpha particles (helium-4 ions). It is an actinide element, the sixth transuranium element to be synthesized, and has the second-highest atomic mass of all the elements that have been produced in amounts large enough to see with the unaided eye (after einsteinium).
Einsteinium is a synthetic element with the symbol Es and atomic number 99. As a member of the actinide series, it is the seventh transuranic element. It was discovered as a component of the debris of the first hydrogen bomb explosion in 1952, and named after Albert Einstein. Owing to the small amounts of produced einsteinium and the short half-life of its most easily produced isotope, there are currently almost no practical applications for it outside basic scientific research.
Fermium is a synthetic element with the symbol Fm and atomic number 100. It is an actinide and the heaviest element that can be formed by neutron bombardment of lighter elements, and hence the last element that can be prepared in macroscopic quantities. Named for the Enrico Fermi.
Mendelevium is a synthetic element with the symbol Md (formerly Mv) and atomic number 101. A metallic radioactive transuranic element in the actinide series, it is the first element by an atomic number that currently cannot be produced in macroscopic quantities through neutron bombardment of lighter elements.
Nobelium is a synthetic chemical element with the symbol No and atomic number 102. It is named in honor of Alfred Nobel, the inventor of dynamite and benefactor of science. A radioactive metal, it is the tenth transuranic element and is the penultimate member of the actinide series. Like all elements with an atomic number over 100, nobelium can only be produced in particle accelerators by bombarding lighter elements with charged particles.
Lawrencium is a synthetic chemical element with the symbol Lr (formerly Lw) and atomic number 103. It is named in honor of Ernest Lawrence, inventor of the cyclotron, a device that was used to discover many artificial radioactive elements. A radioactive metal, lawrencium is the eleventh transuranic element and is also the final member of the actinide series.
Post-transition Metals
Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a blue-silvery appearance when oxidation is removed. Zinc is the 24th most abundant element in Earth’s crust and has five stable isotopes.
Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. It was discovered in 1817 simultaneously by Stromeyer and Hermann, both in Germany, as an impurity in zinc carbonate.
Mercury is a chemical element with the symbol Hg and atomic number 80. It is commonly known as quicksilver and was formerly named hydrargyrum. A heavy, silvery d-block element, mercury is the only metallic element that is liquid at standard conditions for temperature and pressure; the only other element that is liquid under these conditions is the halogen bromine, though metals such as cesium, gallium, and rubidium melt just above room temperature.
Copernicium is a synthetic chemical element with the symbol Cn and atomic number 112. Its known isotopes are extremely radioactive and have only been created in a laboratory. The most stable known isotope, copernicium-285, has a half-life of approximately 28 seconds. Copernicium was first created in 1996 by the GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany. It is named after the astronomer Nicolaus Copernicus.
Aluminum is a chemical element with the symbol Al and atomic number 13. It is a silvery-white, soft, non-magnetic and ductile metal in the boron group. By mass, aluminum makes up about 8% of the Earth’s crust, it is the third most abundant element after oxygen and silicon and the most abundant metal in the crust, though it is less common in the mantle below. The chief ore of aluminum is bauxite. Aluminum metal is highly reactive, such that native specimens are rare and limited to extreme reducing environments. Instead, it is found combined in over 270 different minerals.
Gallium is a chemical element with the symbol Ga and atomic number 31. Elemental gallium is a soft, silvery-blue metal at standard temperature and pressure; however, in its liquid state, it becomes silvery white. Elemental gallium is a liquid at temperatures greater than 29.76 °C (85.57 °F), above room temperature, but below the normal human body temperature of 37 °C (99 °F). Hence, the metal will melt in a person’s hands.
Indium is a chemical element with the symbol In and atomic number 49. Indium is the softest metal that is not an alkali metal. It is a silvery-white metal that resembles tin in appearance. Indium was discovered in 1863 by Ferdinand Reich and Hieronymous Theodor Richter by spectroscopic methods. They named it for the indigo blue line in its spectrum. Indium was isolated the next year.
Thallium is a chemical element with the symbol Tl and atomic number 81. It is a gray post-transition metal that is not found free in nature. Chemists William Crookes and Claude-Auguste Lamy discovered thallium independently in 1861, in residues of sulfuric acid production.
Tin is a chemical element with the symbol Sn (from Latin: stannum) and atomic number 50. Tin is a silvery metal that characteristically has a faint yellow hue. Tin, like indium, is soft enough to be cut without much force.
Lead is a chemical element with the symbol Pb (from the Latin plumbum) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, lead is silvery with a hint of blue. Lead has the highest atomic number of any stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements.
Bismuth is a chemical element with the symbol Bi and atomic number 83. It is a pentavalent post-transition metal and one of the pnictogens with chemical properties resembling its lighter homologs arsenic and antimony.
Polonium is a chemical element with the symbol Po and atomic number 84. Rare and highly radioactive metal with no stable isotopes, polonium is chemically similar to selenium and tellurium, though its metallic character resembles that of its horizontal neighbors in the periodic table: thallium, lead, and bismuth.
Noble Gases
The noble gases are the chemical elements in group 18 of the periodic table. They are the most stable due to having the maximum number of valence electrons their outer shell can hold. Therefore, they rarely react with other elements since they are already stable.
Other characteristics of the noble gases are that they all conduct electricity, fluoresce, are odorless and colorless, and are used in man
Helium is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas, the first in the noble gas group in the periodic table. Its boiling point is the lowest among all the elements. Helium is the second lightest and second most abundant element in the observable universe.
Neon is a chemical element with the symbol Ne and atomic number 10. It is a noble gas.[10] Neon is a colorless, odorless, inert monatomic gas under standard conditions, with about two-thirds the density of air. Neon is chemically inert, and no uncharged neon compounds are known.
Argon is a chemical element with the symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third-most abundant gas in the Earth’s atmosphere, at 0.934% (9340 ppmv). Argon is the most abundant noble gas in Earth’s crust, comprising 0.00015% of the crust.
Krypton is a chemical element with the symbol Kr and atomic number 36. It is a colorless, odorless, tasteless noble gas that occurs in trace amounts in the atmosphere and is often used with other rare gases in fluorescent lamps. With rare exceptions, krypton is chemically inert.
Xenon is a chemical element with the symbol Xe and atomic number 54. It is a colorless, dense, odorless noble gas found in Earth’s atmosphere in trace amounts. Although generally unreactive, xenon can undergo a few chemical reactions such as the formation of xenon hexafluoroplatinate, the first noble gas compound to be synthesized.
Radon is a chemical element with the symbol Rn and atomic number 86. It is a radioactive, colorless, odorless, tasteless noble gas. It occurs naturally in minute quantities as an intermediate step in the normal radioactive decay chains through which thorium and uranium slowly decay into lead and various other short-lived radioactive elements; radon itself is the immediate decay product of radium.
Unknown Chemical Properties
These elements are relatively new discoveries. Very little is known about these elements and their properties. Some of the elements were considered to be part of one group and then displayed properties associated with another group, so putting them into any of the above categories is not currently possible, hence the name.
Meitnerium is a synthetic chemical element with the symbol Mt and atomic number 109. It is an extremely radioactive synthetic element (an element not found in nature, but can be created in a laboratory). The most stable known isotope, meitnerium-278, has a half-life of 4.5 seconds.
Darmstadtium is a synthetic chemical element with the symbol Ds and atomic number 110. It is an extremely radioactive synthetic element. The most stable known isotope, darmstadtium-281, has a half-life of approximately 12.7 seconds. Darmstadtium was first created in 1994 by the GSI Helmholtz Centre for Heavy Ion Research near the city of Darmstadt, Germany, after which it was named.
Roentgenium is a chemical element with the symbol Rg and atomic number 111. It is an extremely radioactive synthetic element that can be created in a laboratory but is not found in nature. The most stable known isotope, roentgenium-282, has a half-life of 100 seconds, although the unconfirmed roentgenium-286 may have a longer half-life of about 10.7 minutes. Roentgenium was first created in 1994 by the GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany.
Nihonium is a synthetic chemical element with the symbol Nh and atomic number 113. It is extremely radioactive; its most stable known isotope, nihonium-286, has a half-life of about 10 seconds.
Flerovium is a superheavy artificial chemical element with the symbol Fl and atomic number 114. It is an extremely radioactive synthetic element. The element is named after the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research in Dubna, Russia, where the element was discovered in 1998.
Moscovium is a synthetic chemical element with the symbol Mc and atomic number 115. It was first synthesized in 2003 by a joint team of Russian and American scientists at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. In December 2015, it was recognized as one of four new elements by the Joint Working Party of international scientific bodies IUPAC and IUPAP.
Livermorium is a synthetic chemical element with the symbol Lv and has an atomic number of 116. It is an extremely radioactive element that has only been created in the laboratory and has not been observed in nature. Four isotopes of livermorium are known, with mass numbers between 290 and 293 inclusive; the longest-lived among them is livermorium-293 with a half-life of about 60 milliseconds.
Tennessine is a synthetic chemical element with the symbol Ts and atomic number 117. It is the second-heaviest known element and the penultimate element of the 7th period of the periodic table. The discovery of tennessine was officially announced in Dubna, Russia, by a Russian–American collaboration in April 2010, which makes it the most recently discovered element as of 2019.
Oganesson is a synthetic chemical element with the symbol Og and atomic number 118. It was first synthesized in 2002 at the Joint Institute for Nuclear Research (JINR) in Dubna, near Moscow, Russia, by a joint team of Russian and American scientists.
We hope you enjoyed reading our guide to all the elements of the Periodic Table, we’re sure that you have some questions, just comment below and we’ll do our best to answer any that you have. A big thank you to the team at Wikipedia for help in compiling this guide.
