Periodic Table of Elements

Helium

A chemical element with 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.

Gallium

A chemical element with symbol Ga and atomic number 31. It does not occur as a free element in nature, but as compounds in trace amounts in zinc ores and in bauxite.

Gadolinium

A chemical element with symbol Gd and atomic number 64. It is a silvery-white, malleable and ductile rare-earth metal. It is found in nature only in combined form.

Germanium

A chemical element with symbol Ge and atomic number 32. It is a lustrous, hard, grayish-white metalloid in the carbon group, chemically similar to its group neighbors tin and silicon.

Californium

A radioactive metallic chemical element with symbol Cf and atomic number 98. The element was first made in 1950 at the University of California Radiation Laboratory in Berkeley, by bombarding curium with alpha particles.

Nobelium

A synthetic chemical element with symbol No and atomic number 102. It is named in honor of Alfred Nobel, the inventor of dynamite and benefactor of science.

Mendelevium

A synthetic element with chemical symbol Md and atomic number 101.

Einsteinium

A synthetic element with symbol Es and atomic number 99. It is the seventh transuranic element, and an actinide.

Fermium

A synthetic element with symbol Fm and atomic number 100. It is a member of the actinide series.

Berkelium

A transuranic radioactive chemical element with symbol Bk and atomic number 97. It is a member of the actinide and transuranium element series.

Curium

A transuranic radioactive chemical element with 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.

Hafnium

A chemical element with symbol Hf and atomic number 72. A lustrous, silvery gray, tetravalent transition metal, hafnium chemically resembles zirconium and is found in zirconium minerals.

Mercury

A chemical element with symbol Hg and atomic number 80. It is commonly known as quicksilver and was formerly named hydrargyrum.

Carbon

A chemical element with symbol C and atomic number 6. On the periodic table, it is the first of six elements in column, which have in common the composition of their outer electron shell.

Calcium

A chemical element with symbol Ca and atomic number 20. It is a soft gray Group 2 alkaline earth metal, fifth-most-abundant element by mass in the Earth's crust.

Radium

A chemical element with 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

Ytterbium

A chemical element with symbol Yb and atomic number 70. It is the fourteenth and penultimate element in the lanthanide series, which is the basis of the relative stability of its +2 oxidation state.

Zinc

A chemical element with symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table.

Actinium

A radioactive chemical element with symbol Ac and atomic number 89, which was discovered in 1899. It was the first non-primordial radioactive element to be isolated.

Aluminum

A chemical element in the boron group with symbol Al and atomic number 13. It is a silvery-white, soft, nonmagnetic, ductile metal.

Lead

A chemical element in the carbon group with symbol Pb and atomic number 82. It is a soft, malleable and heavy post-transition metal.

Erbium

A chemical element in the lanthanide series, with symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural it is always found in chemical combination with other elements on Earth.

Hydrogen

A chemical element with chemical symbol H and atomic number 1. With an atomic weight of 1.00794 u, this is the lightest element on the periodic table

Argon

A chemical element with symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas.

Arsenic

A chemical element with symbol As and atomic number 33. Occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal; It is a metalloid.

Boron

A chemical element with 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.

Barium

A chemical element with symbol Ba and atomic number 56. It is the fifth element in Group 2, a soft silvery metallic alkaline earth metal.

Beryllium

A chemical element with 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.

Bohrium

A chemical element with symbol Bh and atomic number 107. It is named after Danish physicist Niels Bohr. It is a synthetic element and radioactive; the most stable known isotope, ²⁷⁰Bh, has a half-life of approximately 61 seconds

Bromine

A chemical element with symbol Br and atomic number 35. It is a halogen. The element was isolated independently by two chemists, Carl Jacob Löwig and Antoine Jérôme Balard.

Cadmium

A chemical element with symbol Cd and atomic number 48. This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury.

Chlorine

A chemical element with symbol Cl and atomic number 17. It has a relative atomic mass of about 35.5. It is in the halogen group and is the second lightest halogen, following fluorine.

Chromium

A chemical element with symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-grey, lustrous, hard and brittle metal which takes a high polish, resists tarnishing, and has a high melting point.

Caesium

A chemical element with symbol Cs and atomic number 55. It is a soft, silvery-gold alkali metal with a melting point of 28.5 °C, which makes it one of only five elemental metals that are liquid at or near room temperature.

Copper

A chemical element with symbol Cu 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 reddish-orange color.

Dubnium

A chemical element with symbol Db and atomic number 105. It is named after the town of Dubna in Russia, where it was first produced.

Europium

A chemical element with symbol Eu and atomic number 63. It was isolated in 1901 and is named after the continent of Europe. It is a moderately hard, silvery metal which readily oxidizes in air and water.

Flourine

A chemical element with symbol F and atomic number 9. It is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions.

Iron

A chemical element with symbol Fe and atomic number 26. It is a metal in the first transition series. It is by mass the most common element on Earth, forming much of Earth's outer and inner core

Francium

A chemical element with symbol Fr and atomic number 87. It used to be known as eka-caesium and actinium K. It is the second-least electronegative element, behind only caesium.

Holmium

A chemical element with symbol Ho and atomic number 67. Part of the lanthanide series, it is a rare earth element. This element was discovered by Swedish chemist Per Theodor Cleve.

Iodine

A chemical element with symbol I and atomic number 53. The name is from Greek ἰοειδής ioeidēs, meaning violet or purple, referring to the color of iodine vapor.

Indium

A chemical element with symbol In and atomic number 49. It is a post-transition metal that makes up 0.21 parts per million of the Earth's crust.

Iridium

A chemical element with symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum group.

Potassium

A chemical element with symbol K and atomic number 19. It was first isolated from potash, the ashes of plants, from which its name derives. In the Periodic table, this is one of seven elements in column 1.

Krypton

A chemical element with symbol Kr and atomic number 36. It is a member of group 18 elements.

Lutetium

A chemical element with symbol Lu and atomic number 71. It is a silvery white metal, which resists corrosion in dry, but not in moist air.

Magnesium

A chemical element with 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.

Manganese

A chemical element with 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

Molybdenum

A chemical element with symbol Mo and atomic number 42. The name is from Neo-Latin molybdaenum, from Ancient Greek Μόλυβδος molybdos, meaning lead, since its ores were confused with lead ores.

Meitnerium

A chemical element with symbol Mt and atomic number 109. It is an extremely radioactive synthetic element. The most stable isotope, this element has a half-life of 7.6 seconds

Nitrogen

A chemical element with symbol N and atomic number 7. It is the lightest pnictogen, and at room temperature it is a transparent, odorless diatomic gas.

Sodium

A chemical element with symbol Na and atomic number 11. It is a soft, silver-white, highly reactive metal.

Niobium

A chemical element with symbol Nb and atomic number 41. It is a soft, grey, ductile transition metal, which is often found in the pyrochlore mineral, the main commercial source for niobium, and columbite

Neodymium

A chemical element with symbol Nd and atomic number 60. It is a soft silvery metal that tarnishes in air. It was discovered in 1885 by the Austrian chemist Carl Auer von Welsbach.

Neon

A chemical element with symbol Ne and atomic number 10. It is in group 18 of the periodic table. It is a colorless, odorless, inert monatomic gas under standard conditions, with about two-thirds the density of air.

Nickel

A chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. This element belongs to the transition metals and is hard and ductile.

Neptunium

A chemical element with symbol Np and atomic number 93. A radioactive actinide metal, it is the first transuranic element.

Oxygen

A chemical element with symbol O and atomic number 8. It is a member of the chalcogen group on the periodic table and is a highly reactive nonmetal and oxidizing agent that readily forms oxides.

Phosphorous

A chemical element with symbol P and atomic number 15. Exists in two major forms: red and white; but because it is highly reactive, it is never found as a free element on Earth.

Protactinium

A chemical element with symbol Pa and atomic number 91. It is a dense, silvery-gray metal which readily reacts with oxygen, water vapor and inorganic acids.

Palladium

A chemical element with symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston.

Polonium

A chemical element with symbol Po and atomic number 84. A rare and highly radioactive metal with no stable isotopes, it is chemically similar to selenium and tellurium.

Praseodymium

A chemical element with symbol Pr and atomic number 59. It is a soft, silvery, malleable and ductile metal in the lanthanide group. It is valued for its magnetic, electrical, chemical, and optical properties.

Platinum

A chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, gray-white transition metal.

Rubidium

A chemical element with symbol Rb and atomic number 37. It is a soft, silvery-white metallic element of the alkali metal group, with an atomic mass of 85.4678.

Rhenium

A chemical element with symbol Re and atomic number 75. It is a silvery-white, heavy, third-row transition metal in group 7 of the periodic table

Rutherfordium

A chemical element with symbol Rf and atomic number 104, named in honor of physicist Ernest Rutherford. It is a synthetic element and radioactive; the most stable known isotope, ²⁶⁷Rf, has a half-life of approximately 1.3 hours.

Radon

A chemical element with symbol Rn and atomic number 86. It is a radioactive, colorless, odorless, tasteless noble gas, occurring naturally as a decay product of radium. Its most stable isotope, ²²²Rn, has a half-life of 3.8 days.

Ruthenium

A chemical element with 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

Sulfur

A chemical element with symbol S and atomic number 16. It is an abundant, multivalent non-metal. Under normal conditions, its atoms form cyclic octatomic molecules with chemical formula S₈.

Antimony

A chemical element with symbol Sb and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite.

Scandium

A chemical element with symbol Sc and atomic number 21. A silvery-white metallic d-block element, it has historically been sometimes classified as a rare earth element, together with yttrium and the lanthanides

Selenium

A chemical element with symbol Se and atomic number 34. It is a nonmetal with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium.

Silicon

A chemical element with symbol Si and atomic number 14. It is a tetravalent metalloid, more reactive than germanium, the metalloid directly below it in the periodic table. Controversy about silicon's character dates to its discovery.

Samarium

A chemical element with symbol Sm and atomic number 62. It is a moderately hard silvery metal that readily oxidizes in air. Being a typical member of the lanthanide series, it usually assumes the oxidation state +3

Strontium

A chemical element with symbol Sr and atomic number 38. An alkaline earth metal, it is a soft silver-white or yellowish metallic element that is highly reactive chemically. The metal turns yellow when it is exposed to air.

Tantalum

A chemical element with symbol Ta and atomic number 73. Previously known as tantalium, its name comes from Tantalus, a villain from Greek mythology

Terbium

A chemical element with 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.

Technetium

A chemical element with symbol Tc and atomic number 43. It is the lightest element of which all isotopes are radioactive; none are stable. Only one other such element, promethium, is followed by elements with stable isotopes

Tellurium

A chemical element with symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. It is chemically related to selenium and sulfur. It is occasionally found in native form as elemental crystals.

Thorium

A chemical element with symbol Th and atomic number 90. A radioactive actinide metal, it is one of only two significantly radioactive elements that still occur naturally in large quantities as a primordial element (the other being uranium).

Titanium

A chemical element with symbol Ti and atomic number 22. It is a lustrous transition metal with a silver color, low density and high strength. It is highly resistant to corrosion in sea water, aqua regia, and chlorine.

Thallium

A chemical element with symbol Tl and atomic number 81. This soft gray post-transition metal is not found free in nature. When isolated, it resembles tin, but discolors when exposed to air.

Thulium

A chemical element with symbol Tm and atomic number 69. It is the thirteenth and antepenultimate element in the lanthanide series.

Uranium

A chemical element with symbol U and atomic number 92. It is a silvery-white metal in the actinide series of the periodic table. Its atom has 92 protons and 92 electrons, of which 6 are valence electrons.

Vanadium

A chemical element with symbol V and atomic number 23. It is a hard, silvery grey, ductile, and malleable transition metal.

Tungsten

A chemical element with symbol W and atomic number 74.

Xenon

A chemical element with symbol Xe and atomic number 54. It is a colorless, dense, odorless noble gas found in the Earth's atmosphere in trace amounts.

Yitrium

A chemical element with 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".

Zirconium

A chemical element with symbol Zr and atomic number 40.

Gold

A chemical element with the symbol Au and the atomic number 79. In its purest form, it is a bright, slightly reddish yellow, dense, soft, malleable and ductile metal. Chemically, gold is a transition metal and a group 11 element.

Bismuth

A chemical element with the symbol Bi and the atomic number 83. Bismuth, a pentavalent post-transition metal and one of the pnictogens.

Dysprosium

A chemical element with the symbol Dy and atomic number 66. It is a rare earth element with a metallic silver luster. It is never found in nature as a free element, though it is found in various minerals, such as xenotime.

Lithium

A chemical element with the symbol Li and atomic number 3. It is a soft, silver-white metal belonging to the alkali metal group of chemical elements. Under standard conditions, it is the lightest metal and the least dense solid element.

Tin

A chemical element with the symbol Sn and atomic number 50, is a post-transition metal in group 14 of the periodic table. It is obtained chiefly from the mineral cassiterite, which contains tin dioxide, SnO₂.

Astatine

A radioactive chemical element with the chemical symbol At and atomic number 85, and is the rarest naturally occurring element on the Earth's crust. It occurs on Earth as the decay product of various heavier elements.

Americium

A radioactive transuranic chemical element with symbol Am and atomic number 95. This member of the actinide series is located in the periodic table under the lanthanide element europium, and thus by analogy was named after the Americas.

Cerium

A soft, ductile, silvery-white metallic chemical element with symbol Ce and atomic number 58. It tarnishes rapidly when exposed to air and is soft enough to be cut with a knife.

Lanthanum

A soft, ductile, silvery-white metallic chemical element with symbol La and atomic number 57. It tarnishes rapidly when exposed to air and is soft enough to be cut with a knife.

Lawrencium

A synthetic chemical element with chemical symbol Lr 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

Periodic Table

A table of the chemical elements arranged in order of atomic number, usually in rows, so that elements with similar atomic structure (and hence similar chemical properties) appear in vertical columns.

Plutonium

A transuranic radioactive chemical element with 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.

Promethium

Originally prometheum, is a chemical element with the symbol Pm and atomic number 61. All of its isotopes are radioactive.

Silver

The metallic element with the atomic number 47. Its symbol is Ag, from the Latin argentum, derived from the Greek ὰργὀς, and ultimately from a Proto-Indo-European language root reconstructed as *h₂erǵ-, "grey" or "shining."

Seaborgium

a chemical element with symbol Sg and atomic number 106. It is named after the American nuclear chemist Glenn T. Seaborg, and is the first and so far only element to be named after a person who was alive when the name was announced.