Periodic table of elements 

Symbol Ac

Discovery and first isolation Friedrich Oskar Giesel (1902)

Named by André-Louis Debierne (1899)

Appearance silvery-white, glowing with an eerie blue light; sometimes with a golden cast

Mass number [227]

Atomic number (Z) 89

Group group 3

Period period 7

Block d-block

Element category  actinide, sometimes considered a transition metal

Electron configuration [Rn] 6d1 7s2

Electrons per shell 2, 8, 18, 32, 18, 9, 2

Symbol Ag

Discovery before 5000 BC

Appearance lustrous white metal

Standard atomic weight Ar, std(Ag) 107.8682(2)

Atomic number (Z) 47

Group group 11

Period period 5

Block d-block

Element category  transition metal

Electron configuration [Kr] 4d10 5s1

Electrons per shell

2, 8, 18, 18, 1

Atomic number (Z) 13

Naming after alumina (aluminium oxide), itself named after mineral alum

Prediction Antoine Lavoisier (1782)

Discovery and first isolation Hans Christian Ørsted (1824)

Named by Humphry Davy (1812)

Appearance silvery gray metallic

Standard atomic weight Ar, std(Al) 26.9815384(3)

Group group 13 (boron group)

Period period 3

Block p-block

Element category  Post-transition metal, [2][a] sometimes considered a metalloid

Electron configuration [Ne] 3s2 3p1

Electrons per shell 2, 8, 3

Symbol Am

Naming after the Americas

Discovery Glenn T. Seaborg, Ralph A. James, Leon O. Morgan, Albert Ghiorso (1944)

Appearance silvery white

Mass number [243]

Atomic number (Z) 95

Group group n/a

Period period 7

Block f-block

Element category  actinide

Electron configuration [Rn] 5f7 7s2

Electrons per shell

2, 8, 18, 32, 25, 8, 2

Symbol Ar

Discovery and first isolation Lord Rayleigh and William Ramsay (1894)

Atomic number (Z) 18

Appearance colorless gas exhibiting a lilac/violet glow when placed in an electric field

Standard atomic weight Ar, std(Ar) [39.792, 39.963] conventional: 39.95

Group group 18 (noble gases)

Period period 3

Block p-block

Element category  noble gas

Electron configuration [Ne] 3s2 3p6

Electrons per shell

2, 8, 8

Symbol As

Discovery Arabic alchemists (before AD 815)

Appearance metallic grey

Standard atomic weight Ar, std(As) 74.921595(6)

Atomic number (Z) 33

Group group 15 (pnictogens)

Period period 4

Block p-block

Element category  metalloid

Electron configuration [Ar] 3d10 4s2 4p3

Electrons per shell

2, 8, 18, 5

Symbol At

Naming after Greek astatos (αστατος), meaning "unstable"

Discovery Dale R. Corson, Kenneth Ross MacKenzie, Emilio Segrè (1940)

Appearance unknown, probably metallic

Mass number [210]

Atomic number (Z) 85

Group group 17 (halogens)

Period period 6

Block p-block

Element category  metalloid, sometimes classified as a nonmetal, or a metal[1][2]

Electron configuration [Xe] 4f14 5d10 6s2 6p5

Electrons per shell

2, 8, 18, 32, 18, 7

Symbol Au

Naming from Latin aurum, meaning gold

Discovery In the Middle East (before 6000 BCE)

Appearance metallic yellow

Standard atomic weight Ar, std(Au) 196.966570(4)

Atomic number (Z) 79

Group group 11

Period period 6

Block d-block

Element category  transition metal

Electron configuration [Xe] 4f14 5d10 6s1

Electrons per shell

2, 8, 18, 32, 18, 1

Symbol B

Discovery Joseph Louis Gay-Lussac and Louis Jacques Thénard (30 June 1808)

First isolation Humphry Davy (9 July 1808)

Appearance black-brown

Standard atomic weight Ar, std(B) [10.806, 10.821] conventional: 10.81

Atomic number (Z) 5

Group group 13 (boron group)

Period period 2

Block p-block

Element category  metalloid

Electron configuration [He] 2s2 2p1

Electrons per shell

2, 3

Symbol Ba

Discovery Carl Wilhelm Scheele (1772)

First isolation Humphry Davy (1808)

Appearance silvery gray; with a pale yellow tint

Standard atomic weight Ar, std(Ba) 137.327(7)

Atomic number (Z) 56

Group group 2 (alkaline earth metals)

Period period 6

Block s-block

Element category  alkaline earth metals

Electron configuration [Xe] 6s2

Electrons per shell

2, 8, 18, 18, 8, 2

Symbol Be

Discovery Louis Nicolas Vauquelin (1798)

First isolation Friedrich Wöhler & Antoine Bussy (1828)

Appearance white-gray metallic

Standard atomic weight Ar, std(Be) 9.0121831(5)

Atomic number (Z) 4

Group group 2 (alkaline earth metals)

Period period 2

Block s-block

Element category  alkaline earth metal

Electron configuration [He] 2s2

Electrons per shell

2, 2

Symbol Bh

Naming after Niels Bohr

Discovery Gesellschaft für Schwerionenforschung (1981)

Mass number [270] (unconfirmed: 278)

Atomic number (Z) 107

Group group 7

Period period 7

Block d-block

Element category  transition metal

Electron configuration [Rn] 5f14 6d5 7s2[1][2]

Electrons per shell

2, 8, 18, 32, 32, 13, 2

Symbol Bi

Discovery Arabic alchemists (before AD 1000)

Appearance lustrous brownish silver

Standard atomic weight Ar, std(Bi) 208.98040(1)

Atomic number (Z) 83

Group group 15 (pnictogens)

Period period 6

Block p-block

Element category  post-transition metal

Electron configuration [Xe] 4f14 5d10 6s2 6p3

Electrons per shell

2, 8, 18, 32, 18, 5

Symbol Bk

Naming after Berkeley, California, where it was discovered

Discovery Lawrence Berkeley National Laboratory (1949)

Appearance silvery

Mass number [247]

Atomic number (Z) 97

Group group n/a

Period period 7

Block f-block

Element category  actinide

Electron configuration [Rn] 5f9 7s2

Electrons per shell

2, 8, 18, 32, 27, 8, 2

Symbol Br

Discovery and first isolation Antoine Jérôme Balard and Carl Jacob Löwig (1825)

Appearance reddish-brown

Standard atomic weight Ar, std(Br) [79.901, 79.907] conventional: 79.904

Atomic number (Z) 35

Group group 17 (halogens)

Period period 4

Block p-block

Element category  reactive nonmetal

Electron configuration [Ar] 3d10 4s2 4p5

Electrons per shell

2, 8, 18, 7

Symbol C

Discovery Egyptians and Sumerians (3750 BCE)

Recognized as an element by Antoine Lavoisier (1789)

Appearance 

graphite: black

diamond: clear

Standard atomic weight Ar, std(C) [12.0096, 12.0116] conventional: 12.011

Atomic number (Z) 6

Group group 14 (carbon group)

Period period 2

Block p-block

Element category  reactive nonmetal, sometimes considered a metalloid

Electron configuration [He] 2s2 2p2

Electrons per shell

2, 4

Symbol Ca

Discovery and first isolation Humphry Davy (1808)

Appearance dull gray, silver; with a pale yellow tint

Standard atomic weight Ar, std(Ca) 40.078(4)

Atomic number (Z) 20

Group group 2 (alkaline earth metals)

Period period 4

Block s-block

Element category  alkaline earth metal

Electron configuration [Ar] 4s2

Electrons per shell

2, 8, 8, 2

Symbol Cd

Discovery and first isolation Karl Samuel Leberecht Hermann and Friedrich Stromeyer (1817)

Named by Friedrich Stromeyer (1817)

Appearance silvery bluish-gray metallic

Standard atomic weight Ar, std(Cd) 112.414(4)

Atomic number (Z) 48

Group group 12

Period period 5

Block d-block

Element category  post-transition metal, alternatively considered a transition metal

Electron configuration [Kr] 4d10 5s2

Electrons per shell

2, 8, 18, 18, 2

Symbol Ce

Naming after dwarf planet Ceres, itself named after Roman deity of agriculture Ceres

Discovery Martin Heinrich Klaproth, Jöns Jakob Berzelius, Wilhelm Hisinger (1803)

First isolation Carl Gustaf Mosander (1838)

Appearance silvery white

Standard atomic weight Ar, std(Ce) 140.116(1)

Atomic number (Z) 58

Group group n/a

Period period 6

Block f-block

Element category  lanthanide

Electron configuration [Xe] 4f1 5d1 6s2[2]

Electrons per shell

2, 8, 18, 19, 9, 2

Symbol Cf

Naming after California, where it was discovered

Discovery Lawrence Berkeley National Laboratory (1950)

Appearance silvery

Mass number [251]

Atomic number (Z) 98

Group group n/a

Period period 7

Block f-block

Element category  actinide

Electron configuration [Rn] 5f10 7s2[1]

Electrons per shell

2, 8, 18, 32, 28, 8, 2

Symbol Cl

Discovery and first isolation Carl Wilhelm Scheele (1774)

Recognized as an element by Humphry Davy (1808)

Appearance pale yellow-green gas

Standard atomic weight Ar, std(Cl) [35.446, 35.457] conventional: 35.45

Atomic number (Z) 17

Group group 17 (halogens)

Period period 3

Block p-block

Element category  reactive nonmetal

Electron configuration [Ne] 3s2 3p5

Electrons per shell

2, 8, 7

Symbol Cm

Naming named after Marie Skłodowska-Curie and Pierre Curie

Discovery Glenn T. Seaborg, Ralph A. James, Albert Ghiorso (1944)

Appearance silvery metallic, glows purple in the dark

Mass number [247]

Atomic number (Z) 96

Group group n/a

Period period 7

Block f-block

Element category  actinide

Electron configuration [Rn] 5f7 6d1 7s2

Electrons per shell

2, 8, 18, 32, 25, 9, 2

Symbol Co

Discovery and first isolation Georg Brandt (1735)

Appearance hard lustrous bluish gray metal

Standard atomic weight Ar, std(Co) 58.933194(3)

Atomic number (Z) 27

Group group 9

Period period 4

Block d-block

Element category  transition metal

Electron configuration [Ar] 3d7 4s2

Electrons per shell

2, 8, 15, 2

Symbol Cr

Discovery and first isolation Louis Nicolas Vauquelin (1794, 1797)

Appearance silvery metallic

Standard atomic weight Ar, std(Cr) 51.9961(6)

Atomic number (Z) 24

Group group 6

Period period 4

Block d-block

Element category  transition metal

Electron configuration [Ar] 3d5 4s1

Electrons per shell

2, 8, 13, 1

Symbol Cs

Naming from Latin caesius, sky blue, for its spectral colours

Discovery Robert Bunsen and Gustav Kirchhoff (1860)

First isolation Carl Setterberg (1882)

Appearance pale gold

Standard atomic weight Ar, std(Cs) 132.90545196(6)

Atomic number (Z) 55

Group group 1 (alkali metals)

Period period 6

Block s-block

Element category  alkali metal

Electron configuration [Xe] 6s1

Electrons per shell

2, 8, 18, 18, 8, 1

Symbol Cu

Naming after Cyprus, principal mining place in Roman era (Cyprium)

Discovery Middle East (9000 BC)

Appearance red-orange metallic luster

Standard atomic weight Ar, std(Cu) 63.546(3)

Atomic number (Z) 29

Group group 11

Period period 4

Block d-block

Element category  transition metal

Electron configuration [Ar] 3d10 4s1

Electrons per shell

2, 8, 18, 1

Symbol Cn

Naming after Nicolaus Copernicus

Discovery Gesellschaft für Schwerionenforschung (1996)

Mass number [285]

Atomic number (Z) 112

Group group 12

Period period 7

Block d-block

Element category  post-transition metal, alternatively considered a transition metal

Electron configuration [Rn] 5f14 6d10 7s2 (predicted)[1]

Electrons per shell

2, 8, 18, 32, 32, 18, 2 (predicted)

Symbol Db

Naming after Dubna, Moscow Oblast, Russia, site of Joint Institute for Nuclear Research

Discovery independently by the Lawrence Berkeley Laboratory and the Joint Institute for Nuclear Research (1970)

Mass number [268]

Atomic number (Z) 105

Group group 5

Period period 7

Block d-block

Element category  transition metal

Electron configuration [Rn] 5f14 6d3 7s2[3]

Electrons per shell

2, 8, 18, 32, 32, 11, 2

Symbol Ds

Naming after Darmstadt, Germany, where it was discovered

Discovery Gesellschaft für Schwerionenforschung (1994)

Mass number [281]

Atomic number (Z) 110

Group group 10

Period period 7

Block d-block

Element category  unknown chemical properties, but probably a transition metal

Electron configuration [Rn] 5f14 6d8 7s2 (predicted)

Electrons per shell

2, 8, 18, 32, 32, 16, 2 (predicted)

Symbol Dy

Discovery Lecoq de Boisbaudran (1886)

Appearance silvery white

Standard atomic weight Ar, std(Dy) 162.500(1)

Atomic number (Z) 66

Group group n/a

Period period 6

Block f-block

Element category  lanthanide

Electron configuration [Xe] 4f10 6s2

Electrons per shell

2, 8, 18, 28, 8, 2

Symbol Er

Naming after Ytterby (Sweden), where it was mined

Discovery Carl Gustaf Mosander (1843)

Appearance silvery white

Standard atomic weight Ar, std(Er) 167.259(3)

Atomic number (Z) 68

Group group n/a

Period period 6

Block f-block

Element category  lanthanide

Electron configuration [Xe] 4f12 6s2

Electrons per shell

2, 8, 18, 30, 8, 2

Symbol Es

Naming after Albert Einstein

Discovery Lawrence Berkeley National Laboratory (1952)

Appearance silvery; glows blue in the dark

Mass number [252]

Atomic number (Z) 99

Group group n/a

Period period 7

Block f-block

Element category  actinide

Electron configuration [Rn] 5f11 7s2

Electrons per shell

2, 8, 18, 32, 29, 8, 2

Symbol Eu

Naming after Europe

Discovery and first isolation Eugène-Anatole Demarçay (1896, 1901)

Appearance silvery white, with a pale yellow tint; but rarely seen without oxide discoloration

Standard atomic weight Ar, std(Eu) 151.964(1)

Atomic number (Z) 63

Group group n/a

Period period 6

Block f-block

Element category  lanthanide

Electron configuration [Xe] 4f7 6s2

Electrons per shell

2, 8, 18, 25, 8, 2

Symbol F

Naming after the mineral fluorite, itself named after Latin fluo (to flow, in smelting)

Discovery André-Marie Ampère (1810)

First isolation Henri Moissan (June 26, 1886)

Named by Humphry Davy

Appearance gas: very pale yellow

liquid: bright yellow

solid: alpha is opaque, beta is transparent

Standard atomic weight Ar, std(F) 18.998403163(6)

Atomic number (Z) 9

Group group 17 (halogens)

Period period 2

Block p-block

Element category  reactive nonmetal

Electron configuration [He] 2s2 2p5[2]

Electrons per shell

2, 7

Symbol Fl

Naming after Flerov Laboratory of Nuclear Reactions (itself named after Georgy Flyorov)

Discovery Joint Institute for Nuclear Research (JINR) and Lawrence Livermore National Laboratory (LLNL) (1999)

Mass number [289] (unconfirmed: 290)

Atomic number (Z) 114

Group group 14 (carbon group)

Period period 7

Block p-block

Element category  unknown chemical properties, but probably a post-transition metal

Electron configuration [Rn] 5f14 6d10 7s2 7p2 (predicted)[2]

Electrons per shell

2, 8, 18, 32, 32, 18, 4 (predicted)

Symbol Fe

Discovery before 5000 BC

Appearance lustrous metallic with a grayish tinge

Standard atomic weight Ar, std(Fe) 55.845(2)

Atomic number (Z) 26

Group group 8

Period period 4

Block d-block

Element category  transition metal

Electron configuration [Ar] 3d6 4s2

Electrons per shell

2, 8, 14, 2

Symbol Fm

Naming after Enrico Fermi

Discovery Lawrence Berkeley National Laboratory (1952)

Mass number [257]

Atomic number (Z) 100

Group group n/a

Period period 7

Block f-block

Element category  actinide

Electron configuration [Rn] 5f12 7s2

Electrons per shell

2, 8, 18, 32, 30, 8, 2

Symbol Fr

Naming after France, homeland of the discoverer

Discovery and first isolation Marguerite Perey (1939)

Mass number [223]

Atomic number (Z) 87

Group group 1 (alkali metals)

Period period 7

Block s-block

Element category  alkali metal

Electron configuration [Rn] 7s1

Electrons per shell

2, 8, 18, 32, 18, 8, 1

Symbol Ga

Naming after Gallia (Latin for: France), homeland of the discoverer

Prediction Dmitri Mendeleev (1871)

Discovery and first isolation Lecoq de Boisbaudran (1875)

Appearance silvery blue

Standard atomic weight Ar, std(Ga) 69.723(1)

Atomic number (Z) 31

Group group 13 (boron group)

Period period 4

Block p-block

Element category  post-transition metal

Electron configuration [Ar] 3d10 4s2 4p1

Electrons per shell

2, 8, 18, 3

Symbol Gd

Naming after the mineral Gadolinite (itself named after Johan Gadolin)

Discovery Jean Charles Galissard de Marignac (1880)

First isolation Lecoq de Boisbaudran (1886)

Appearance silvery white

Standard atomic weight Ar, std(Gd) 157.25(3)

Atomic number (Z) 64

Group group n/a

Period period 6

Block f-block

Element category  lanthanide

Electron configuration [Xe] 4f7 5d1 6s2

Electrons per shell

2, 8, 18, 25, 9, 2

Symbol Ge

Naming after Germany, homeland of the discoverer

Prediction Dmitri Mendeleev (1869)

Discovery Clemens Winkler (1886)

Appearance grayish-white

Standard atomic weight Ar, std(Ge) 72.630(8)

Atomic number (Z) 32

Group group 14 (carbon group)

Period period 4

Block p-block

Element category  metalloid

Electron configuration [Ar] 3d10 4s2 4p2

Electrons per shell

2, 8, 18, 4

Symbol H

Discovery Henry Cavendish (1766)

Named by Antoine Lavoisier (1783)

Appearance colorless gas

Standard atomic weight Ar, std(H) [1.00784, 1.00811] conventional: 1.008

Atomic number (Z) 1

Group group 1

Period period 1

Block s-block

Element category  reactive nonmetal

Electron configuration 1s1

Electrons per shell

1

Symbol He

Naming after Helios, Greek Titan of the Sun

Discovery Pierre Janssen, Norman Lockyer (1868)

First isolation William Ramsay, Per Teodor Cleve, Abraham Langlet (1895)

Appearance colorless gas, exhibiting a gray, cloudy glow (or reddish-orange if an especially high voltage is used) when placed in an electric field

Standard atomic weight Ar, std(He) 4.002602(2)

Atomic number (Z) 2

Group group 18 (noble gases)

Period period 1

Block s-block

Element category  noble gas

Electron configuration 1s2

Electrons per shell

2

Symbol Hf

Naming after Hafnia. Latin for: Copenhagen, where it was discovered

Prediction Dmitri Mendeleev (1869)

Discovery and first isolation Dirk Coster and George de Hevesy (1922)

Appearance steel gray

Standard atomic weight Ar, std(Hf) 178.49(2)

Atomic number (Z) 72

Group group 4

Period period 6

Block d-block

Element category  transition metal

Electron configuration [Xe] 4f14 5d2 6s2

Electrons per shell

2, 8, 18, 32, 10, 2

Symbol Hg

Discovery Ancient Egyptians (before 1500 BCE)

Atomic number (Z) 80

Appearance silvery

Standard atomic weight Ar, std(Hg) 200.592(3)

Group group 12

Period period 6

Block d-block

Element category  post-transition metal, alternatively considered a transition metal

Electron configuration [Xe] 4f14 5d10 6s2

Electrons per shell

2, 8, 18, 32, 18, 2

Symbol Ho

Discovery Jacques-Louis Soret and Marc Delafontaine (1878)

Appearance silvery white

Standard atomic weight Ar, std(Ho) 164.930328(7)

Atomic number (Z) 67

Group group n/a

Period period 6

Block f-block

Element category  lanthanide

Electron configuration [Xe] 4f11 6s2

Electrons per shell

2, 8, 18, 29, 8, 2

Symbol Hs

Naming after Hassia, Latin for Hesse, Germany, where it was discovered

Discovery Gesellschaft für Schwerionenforschung (1984)

Mass number [269]

Atomic number (Z) 108

Group group 8

Period period 7

Block d-block

Element category  transition metal

Electron configuration [Rn] 5f14 6d6 7s2[3]

Electrons per shell

2, 8, 18, 32, 32, 14, 2

Symbol I

Discovery and first isolation Bernard Courtois (1811)

Appearance lustrous metallic gray, violet as a gas

Standard atomic weight Ar, std(I) 126.90447(3)

Atomic number (Z) 53

Group group 17 (halogens)

Period period 5

Block p-block

Element category  reactive nonmetal

Electron configuration [Kr] 4d10 5s2 5p5

Electrons per shell

2, 8, 18, 18, 7

Symbol In

Discovery Ferdinand Reich and Hieronymous Theodor Richter (1863)

First isolation Hieronymous Theodor Richter (1864)

Appearance silvery lustrous gray

Standard atomic weight Ar, std(In) 114.818(1)

Atomic number (Z) 49

Group group 13 (boron group)

Period period 5

Block p-block

Element category  post-transition metal

Electron configuration [Kr] 4d10 5s2 5p1

Electrons per shell

2, 8, 18, 18, 3

Symbol Ir

Discovery and first isolation Smithson Tennant (1803)

Appearance silvery white

Standard atomic weight Ar, std(Ir) 192.217(2)

Atomic number (Z) 77

Group group 9

Period period 6

Block d-block

Element category  transition metal

Electron configuration [Xe] 4f14 5d7 6s2

Electrons per shell

2, 8, 18, 32, 15, 2

Symbol K

Discovery and first isolation Humphry Davy (1807)

Appearance silvery gray

Standard atomic weight Ar, std(K) 39.0983(1)

Atomic number (Z) 19

Group group 1 (alkali metals)

Period period 4

Block s-block

Element category  alkali metal

Electron configuration [Ar] 4s1

Electrons per shell

2, 8, 8, 1

Symbol Kr

Discovery and first isolation William Ramsay and Morris Travers (1898)

Appearance colorless gas, exhibiting a whitish glow in an electric field

Standard atomic weight Ar, std(Kr) 83.798(2)

Atomic number (Z) 36

Group group 18 (noble gases)

Period period 4

Block p-block

Element category  noble gas

Electron configuration [Ar] 3d10 4s2 4p6

Electrons per shell

2, 8, 18, 8

Symbol La

Discovery Carl Gustaf Mosander (1838)

Appearance silvery white

Standard atomic weight Ar, std(La) 138.90547(7)

Atomic number (Z) 57

Group group 3

Period period 6

Block d-block

Element category  lanthanide, sometimes considered a transition metal

Electron configuration [Xe] 5d1 6s2

Electrons per shell

2, 8, 18, 18, 9, 2

Symbol Lr

Naming after Ernest Lawrence

Discovery Lawrence Berkeley National Laboratory and Joint Institute for Nuclear Research (1961–1971)

Appearance silvery (predicted)

Mass number [266]

Atomic number (Z) 103

Group group n/a

Period period 7

Block f-block

Element category  actinide, sometimes considered a transition metal

Electron configuration [Rn] 5f14 7s2 7p1

Electrons per shell

2, 8, 18, 32, 32, 8, 3

Symbol Li

Discovery Johan August Arfwedson (1817)

First isolation William Thomas Brande (1821)

Appearance silvery-white

Standard atomic weight Ar, std(Li) [6.938, 6.997] conventional: 6.94

Atomic number (Z) 3

Group group 1 (alkali metals)

Period period 2

Block s-block

Element category  alkali metal

Electron configuration [He] 2s1

Electrons per shell

2, 1

Symbol Lv

Naming after Lawrence Livermore National Laboratory, itself named partly after Livermore, California

Discovery Joint Institute for Nuclear Research and Lawrence Livermore National Laboratory (2000)

Mass number [293]

Atomic number (Z) 116

Group group 16 (chalcogens)

Period period 7

Block p-block

Element category  unknown chemical properties, but probably a post-transition metal

Electron configuration [Rn] 5f14 6d10 7s2 7p4 (predicted)[1]

Electrons per shell

2, 8, 18, 32, 32, 18, 6 (predicted)

Symbol Lu

Naming after Lutetia, Latin for: Paris, in the Roman era

Discovery Carl Auer von Welsbach and Georges Urbain (1906)

First isolation Carl Auer von Welsbach (1906)

Named by Georges Urbain (1906)

Appearance silvery white

Standard atomic weight Ar, std(Lu) 174.9668(1)

Atomic number (Z) 71

Group group n/a

Period period 6

Block f-block

Element category  lanthanide, sometimes considered a transition metal

Electron configuration [Xe] 4f14 5d1 6s2

Electrons per shell

2, 8, 18, 32, 9, 2

Symbol Md

Naming after Dmitri Mendeleev

Discovery Lawrence Berkeley National Laboratory (1955)

Mass number [258]

Atomic number (Z) 101

Group group n/a

Period period 7

Block f-block

Element category  actinide

Electron configuration [Rn] 5f13 7s2

Electrons per shell

2, 8, 18, 32, 31, 8, 2

Symbol Mg

Naming after Magnesia, Greece

Discovery Joseph Black (1755)

First isolation Humphry Davy (1808)

Appearance shiny grey solid

Standard atomic weight Ar, std(Mg) [24.304, 24.307] conventional: 24.305

Atomic number (Z) 12

Group group 2 (alkaline earth metals)

Period period 3

Block s-block

Element category  alkaline earth metal

Electron configuration [Ne] 3s2

Electrons per shell

2, 8, 2

Symbol Mn

Discovery Carl Wilhelm Scheele (1774)

First isolation Johann Gottlieb Gahn (1774)

Appearance silvery metallic

Standard atomic weight Ar, std(Mn) 54.938043(2)

Atomic number (Z) 25

Group group 7

Period period 4

Block d-block

Element category  transition metal

Electron configuration [Ar] 3d5 4s2

Electrons per shell

2, 8, 13, 2

Symbol Mt

Naming after Lise Meitner

Discovery Gesellschaft für Schwerionenforschung (1982)

Mass number [278] (unconfirmed: 282)

Atomic number (Z) 109

Group group 9

Period period 7

Block d-block

Element category  unknown chemical properties, but probably a transition metal[3][4]

Electron configuration [Rn] 5f14 6d7 7s2 (predicted)[3][5]

Electrons per shell

2, 8, 18, 32, 32, 15, 2 (predicted)

Symbol Mo

Discovery Carl Wilhelm Scheele (1778)

First isolation Peter Jacob Hjelm (1781)

Appearance gray metallic

Standard atomic weight Ar, std(Mo) 95.95(1)

Atomic number (Z) 42

Group group 6

Period period 5

Block d-block

Element category  transition metal

Electron configuration [Kr] 4d5 5s1

Electrons per shell

2, 8, 18, 13, 1

Symbol Mc

Naming After Moscow region

Discovery Joint Institute for Nuclear Research and Lawrence Livermore National Laboratory (2003)

Mass number [290]

Atomic number (Z) 115

Group group 15 (pnictogens)

Period period 7

Block p-block

Element category  unknown chemical properties, but probably a post-transition metal

Electron configuration [Rn] 5f14 6d10 7s2 7p3 (predicted)[1]

Electrons per shell

2, 8, 18, 32, 32, 18, 5 (predicted)

Symbol N

Discovery Daniel Rutherford (1772)

Named by Jean-Antoine Chaptal (1790)

Appearance colorless gas, liquid or solid

Standard atomic weight Ar, std(N) [14.00643, 14.00728] conventional: 14.007

Atomic number (Z) 7

Group group 15 (pnictogens)

Period period 2

Block p-block

Element category  reactive nonmetal

Electron configuration [He] 2s2 2p3

Electrons per shell

2, 5

Symbol Na

Discovery and first isolation Humphry Davy (1807)

Appearance silvery white metallic

Standard atomic weight Ar, std(Na) 22.98976928(2)

Atomic number (Z) 11

Group group 1 (alkali metals)

Period period 3

Block s-block

Element category  alkali metal

Electron configuration [Ne] 3s1

Electrons per shell

2, 8, 1

Symbol Nb

Naming after Niobe in Greek mythology, daughter of Tantalus (tantalum)

Discovery Charles Hatchett (1801)

First isolation Christian Wilhelm Blomstrand (1864)

Recognized as a distinct element by Heinrich Rose (1844)

Appearance gray metallic, bluish when oxidized

Standard atomic weight Ar, std(Nb) 92.90637(1)

Atomic number (Z) 41

Group group 5

Period period 5

Block d-block

Element category  transition metal

Electron configuration [Kr] 4d4 5s1

Electrons per shell

2, 8, 18, 12, 1

Symbol Nd

Discovery Carl Auer von Welsbach (1885)

Appearance silvery white

Standard atomic weight Ar, std(Nd) 144.242(3)

Atomic number (Z) 60

Group group n/a

Period period 6

Block f-block

Element category  lanthanide

Electron configuration [Xe] 4f4 6s2

Electrons per shell

2, 8, 18, 22, 8, 2

Symbol Ni

Discovery and first isolation Axel Fredrik Cronstedt (1751)

Appearance lustrous, metallic, and silver with a gold tinge

Standard atomic weight Ar, std(Ni) 58.6934(4)

Atomic number (Z) 28

Group group 10

Period period 4

Block d-block

Element category  transition metal

Electron configuration [Ar] 3d8 4s2 or [Ar] 3d9 4s1

Electrons per shell

2, 8, 16, 2 or 2, 8, 17, 1

Symbol Nh

Naming After Japan (Nihon in Japanese)

Discovery Riken (Japan, first undisputed claim 2004)

JINR (Russia) and Livermore (US, first announcement 2003)

Mass number [286]

Atomic number (Z) 113

Group group 13 (boron group)

Period period 7

Block p-block

Element category  unknown chemical properties, but probably a post-transition metal

Electron configuration [Rn] 5f14 6d10 7s2 7p1 (predicted)[1]

Electrons per shell

2, 8, 18, 32, 32, 18, 3 (predicted)

Symbol No

Prediction William Ramsay (1897)

Discovery and first isolation William Ramsay & Morris Travers (1898)

Appearance colorless gas exhibiting an orange-red glow when placed in an electric field

Standard atomic weight Ar, std(Ne) 20.1797(6)

Atomic number (Z) 10

Group group 18 (noble gases)

Period period 2

Block p-block

Element category  noble gas

Electron configuration [He] 2s2 2p6

Electrons per shell

2, 8

Symbol No

Naming after Alfred Nobel

Discovery Joint Institute for Nuclear Research (1966)

Mass number [259]

Atomic number (Z) 102

Group group n/a

Period period 7

Block f-block

Element category  actinide

Electron configuration [Rn] 5f14 7s2

Electrons per shell

2, 8, 18, 32, 32, 8, 2

Symbol Np

Naming after planet Neptune, itself named after Roman god of the sea Neptune

Discovery Edwin McMillan and Philip H. Abelson (1940)

Appearance silvery metallic

Mass number [237]

Atomic number (Z) 93

Group group n/a

Period period 7

Block f-block

Element category  actinide

Electron configuration [Rn] 5f4 6d1 7s2

Electrons per shell

2, 8, 18, 32, 22, 9, 2

Symbol Og

Naming after Yuri Oganessian

Prediction Hans Peter Jørgen Julius Thomsen (1895)

Discovery Joint Institute for Nuclear Research and Lawrence Livermore National Laboratory (2002)

Mass number [294] (unconfirmed: 295)

Atomic number (Z) 118

Group group 18

Period period 7

Block p-block

Element category  unknown chemical properties, but probably a noble gas

Electron configuration [Rn] 5f14 6d10 7s2 7p6 (predicted)[2][3]

Electrons per shell

2, 8, 18, 32, 32, 18, 8 (predicted)

Symbol O

Discovery Carl Wilhelm Scheele (1771)

Named by Antoine Lavoisier (1777)

Appearance gas: colorless

liquid and solid: pale blue

Standard atomic weight Ar, std(O) [15.99903, 15.99977] conventional: 15.999

Atomic number (Z) 8

Group group 16 (chalcogens)

Period period 2

Block p-block

Element category  reactive nonmetal

Electron configuration [He] 2s2 2p4

Electrons per shell

2, 6

Symbol Os

Discovery and first isolation Smithson Tennant (1803)

Appearance silvery, blue cast

Standard atomic weight Ar, std(Os) 190.23(3)

Atomic number (Z) 76

Group group 8

Period period 6

Block d-block

Element category  transition metal

Electron configuration [Xe] 4f14 5d6 6s2

Electrons per shell

2, 8, 18, 32, 14, 2

Symbol P

Discovery Hennig Brand (1669)

Recognised as an element by Antoine Lavoisier (1777)

Appearance Colourless, waxy white, yellow, scarlet, red, violet, black

Standard atomic weight Ar, std(P) 30.973761998(5)

Atomic number (Z) 15

Group group 15 (pnictogens)

Period period 3

Block p-block

Element category  reactive nonmetal

Electron configuration [Ne] 3s2 3p3

Electrons per shell

2, 8, 5

Symbol Pa

Prediction Dmitri Mendeleev (1869)

Discovery and first isolation Kasimir Fajans and Oswald Helmuth Göhring (1913)

Named by Otto Hahn and Lise Meitner (1917–8)

Appearance bright, silvery metallic luster

Standard atomic weight Ar, std(Pa) 231.03588(1)

Atomic number (Z) 91

Group group n/a

Period period 7

Block f-block

Element category  actinide

Electron configuration [Rn] 5f2 6d1 7s2

Electrons per shell

2, 8, 18, 32, 20, 9, 2

Symbol Pb

Discovery in the Middle East (7000 BCE)

Appearance metallic gray

Standard atomic weight Ar, std(Pb) 207.2(1)

Atomic number (Z) 82

Group group 14 (carbon group)

Period period 6

Block p-block

Element category  post-transition metal

Electron configuration [Xe] 4f14 5d10 6s2 6p2

Electrons per shell

2, 8, 18, 32, 18, 4

Symbol Pd

Naming after asteroid Pallas, itself named after Pallas Athena

Discovery and first isolation William Hyde Wollaston (1802)

Appearance silvery white

Standard atomic weight Ar, std(Pd) 106.42(1)

Atomic number (Z) 46

Group group 10

Period period 5

Block d-block

Element category  transition metal

Electron configuration [Kr] 4d10

Electrons per shell

2, 8, 18, 18

Symbol Pm

Discovery Chien Shiung Wu, Emilio Segrè, Hans Bethe (1942)

First isolation Charles D. Coryell, Jacob A. Marinsky, Lawrence E. Glendenin (1945)

Named by Grace Mary Coryell (1945)

Appearance metallic

Mass number [145]

Atomic number (Z) 61

Group group n/a

Period period 6

Block f-block

Element category  lanthanide

Electron configuration [Xe] 4f5 6s2

Electrons per shell

2, 8, 18, 23, 8, 2

Symbol Po

Naming after Polonia, Latin for Poland, homeland of Marie Curie

Discovery Pierre and Marie Curie (1898)

First isolation Willy Marckwald (1902)

Appearance silvery

Mass number [209]

Atomic number (Z) 84

Group group 16 (chalcogens)

Period period 6

Block p-block

Element category  post-transition metal, but this status is disputed

Electron configuration [Xe] 4f14 5d10 6s2 6p4

Electrons per shell

2, 8, 18, 32, 18, 6

Symbol Pr

Discovery Carl Auer von Welsbach (1885)

Appearance grayish white

Standard atomic weight Ar, std(Pr) 140.90766(1)

Atomic number (Z) 59

Group group n/a

Period period 6

Block f-block

Element category  lanthanide

Electron configuration [Xe] 4f3 6s2

Electrons per shell

2, 8, 18, 21, 8, 2

Symbol Pt

Discovery Antonio de Ulloa (1735)

Appearance silvery white

Standard atomic weight Ar, std(Pt) 195.084(9)

Atomic number (Z) 78

Group group 10

Period period 6

Block d-block

Element category  transition metal

Electron configuration [Xe] 4f14 5d9 6s1

Electrons per shell

2, 8, 18, 32, 17, 1

Symbol Pu

Naming after dwarf planet Pluto, itself named after classical god of the underworld Pluto

Discovery Glenn T. Seaborg, Arthur Wahl, Joseph W. Kennedy, Edwin McMillan (1940–1)

Appearance silvery white, tarnishing to dark gray in air

Mass number [244]

Atomic number (Z) 94

Group group n/a

Period period 7

Block f-block

Element category  actinide

Electron configuration [Rn] 5f6 7s2

Electrons per shell

2, 8, 18, 32, 24, 8, 2

Symbol Ra

Discovery Pierre and Marie Curie (1898)

First isolation Marie Curie (1910)

Appearance silvery white metallic

Mass number [226]

Atomic number (Z) 88

Group group 2 (alkaline earth metals)

Period period 7

Block s-block

Element category  alkaline earth metal

Electron configuration [Rn] 7s2

Electrons per shell

2, 8, 18, 32, 18, 8, 2

Symbol Rb

Discovery Robert Bunsen and Gustav Kirchhoff (1861)

First isolation George de Hevesy

Appearance grey white

Standard atomic weight Ar, std(Rb) 85.4678(3)

Atomic number (Z) 37

Group group 1 (alkali metals)

Period period 5

Block s-block

Element category  alkali metal

Electron configuration [Kr] 5s1

Electrons per shell

2, 8, 18, 8, 1

Symbol Re

Naming after the river Rhine (German: Rhein)

Discovery Masataka Ogawa (1908)

First isolation Masataka Ogawa (1919)

Named by Walter Noddack, Ida Noddack, Otto Berg (1925)

Appearance silvery-grayish

Standard atomic weight Ar, std(Re) 186.207(1)

Atomic number (Z) 75

Group group 7

Period period 6

Block d-block

Element category  transition metal

Electron configuration [Xe] 4f14 5d5 6s2

Electrons per shell

2, 8, 18, 32, 13, 2

Symbol Rf

Naming after Ernest Rutherford

Discovery Joint Institute for Nuclear Research and Lawrence Berkeley National Laboratory (1964, 1969)

Mass number [267]

Atomic number (Z) 104

Group group 4

Period period 7

Block d-block

Element category  transition metal

Electron configuration [Rn] 5f14 6d2 7s2[1][2]

Electrons per shell

2, 8, 18, 32, 32, 10, 2

Symbol Rg

Naming after Wilhelm Röntgen

Discovery Gesellschaft für Schwerionenforschung (1994)

Appearance silvery (predicted)

Mass number [282] (unconfirmed: 286)

Atomic number (Z) 111

Group group 11

Period period 7

Block d-block

Element category  unknown chemical properties, but probably a transition metal

Electron configuration [Rn] 5f14 6d9 7s2 (predicted)[1][2]

Electrons per shell

2, 8, 18, 32, 32, 17, 2 (predicted)

Symbol Rh

Discovery and first isolation William Hyde Wollaston (1804)

Appearance silvery white metallic

Standard atomic weight Ar, std(Rh) 102.90549(2)

Atomic number (Z) 45

Group group 9

Period period 5

Block d-block

Element category  transition metal

Electron configuration [Kr] 4d8 5s1

Electrons per shell

2, 8, 18, 16, 1

Symbol Rn

Discovery Ernest Rutherford and Robert B. Owens (1899)

First isolation William Ramsay and Robert Whytlaw-Gray (1910)

Appearance colorless gas

Mass number [222]

Atomic number (Z) 86

Group group 18 (noble gases)

Period period 6

Block p-block

Element category  noble gas

Electron configuration [Xe] 4f14 5d10 6s2 6p6

Electrons per shell

2, 8, 18, 32, 18, 8

Symbol Ru

Naming after Ruthenia (Latin for: medieval Kyivska Rus' region)

Discovery and first isolation Karl Ernst Claus (1844)

Appearance silvery white metallic

Standard atomic weight Ar, std(Ru) 101.07(2)

Atomic number (Z) 44

Group group 8

Period period 5

Block d-block

Element category  transition metal

Electron configuration [Kr] 4d7 5s1

Electrons per shell

2, 8, 18, 15, 1

Symbol S

Discovery Chinese (before 2000 BCE)

Recognized as an element by Antoine Lavoisier (1777)

Appearance lemon yellow sintered microcrystals

Standard atomic weight Ar, std(S) [32.059, 32.076] conventional: 32.06

Atomic number (Z) 16

Group group 16 (chalcogens)

Period period 3

Block p-block

Element category  reactive nonmetal

Electron configuration [Ne] 3s2 3p4

Electrons per shell

2, 8, 6

Symbol Sb

Discovery Arabic alchemists (before AD 815)

Appearance silvery lustrous gray

Standard atomic weight Ar, std(Sb) 121.760(1)

Atomic number (Z) 51

Group group 15 (pnictogens)

Period period 5

Block p-block

Element category  metalloid

Electron configuration [Kr] 4d10 5s2 5p3

Electrons per shell

2, 8, 18, 18, 5

Symbol Sc

Naming after Scandinavia

Prediction Dmitri Mendeleev (1871)

Discovery and first isolation Lars Fredrik Ni

Appearance silvery white

Standard atomic weight Ar, std(Sc) 44.955908(5)

Atomic number (Z) 21

Group group 3

Period period 4

Block d-block

Element category  transition metal

Electron configuration [Ar] 3d1 4s2

Electrons per shell

2, 8, 9, 2

Symbol Se

Naming after Selene, Greek goddess of the moon

Discovery and first isolation Jöns Jakob Berzelius and Johann Gottlieb Gahn (1817)

Appearance black, red, and gray allotropes

Standard atomic weight Ar, std(Se) 78.971(8)

Atomic number (Z) 34

Group group 16 (chalcogens)

Period period 4

Block p-block

Element category  reactive nonmetal, sometimes considered a metalloid

Electron configuration [Ar] 3d10 4s2 4p4

Electrons per shell

2, 8, 18, 6

Symbol Sg

Naming after Glenn T. Seaborg

Discovery Lawrence Berkeley National Laboratory (1974)

Mass number [269]

Atomic number (Z) 106

Group group 6

Period period 7

Block d-block

Element category  transition metal

Electron configuration [Rn] 5f14 6d4 7s2[1]

Electrons per shell

2, 8, 18, 32, 32, 12, 2

Symbol Si

Naming after Latin 'silex' or 'silicis', meaning flint

Prediction Antoine Lavoisier (1787)

Discovery and first isolation Jöns Jacob Berzelius (1823)

Named by Thomas Thomson (1817)

Appearance crystalline, reflective with bluish-tinged faces

Standard atomic weight Ar, std(Si) [28.084, 28.086] conventional: 28.085

Atomic number (Z) 14

Group group 14 (carbon group)

Period period 3

Block p-block

Element category  metalloid

Electron configuration [Ne] 3s2 3p2

Electrons per shell

2, 8, 4

Symbol Sm

Naming after the mineral samarskite (itself named after Vassili Samarsky-Bykhovets)

Discovery and first isolation Lecoq de Boisbaudran (1879)

Appearance silvery white

Standard atomic weight Ar, std(Sm) 150.36(2)

Atomic number (Z) 62

Group group n/a

Period period 6

Block f-block

Element category  lanthanide

Electron configuration [Xe] 4f6 6s2

Electrons per shell

2, 8, 18, 24, 8, 2

Symbol Sn

Discovery around 3500 BC

Appearance silvery-white (beta, β) or gray (alpha, α)

Standard atomic weight Ar, std(Sn) 118.710(7)

Atomic number (Z) 50

Group group 14 (carbon group)

Period period 5

Block p-block

Element category  post-transition metal

Electron configuration [Kr] 4d10 5s2 5p2

Electrons per shell

2, 8, 18, 18, 4

Symbol Sr

Naming after the mineral strontianite, itself named after Strontian, Scotland

Discovery William Cruickshank (1787)

First isolation Humphry Davy (1808)

Appearance silvery white metallic; with a pale yellow tint

Standard atomic weight Ar, std(Sr) 87.62(1)

Atomic number (Z) 38

Group group 2 (alkaline earth metals)

Period period 5

Block s-block

Element category  alkaline earth metal

Electron configuration [Kr] 5s2

Electrons per shell

2, 8, 18, 8, 2

Symbol Ta

Discovery Anders Gustaf Ekeberg (1802)

Recognized as a distinct element by Heinrich Rose (1844)

Appearance gray blue

Standard atomic weight Ar, std(Ta) 180.94788(2)

Atomic number (Z) 73

Group group 5

Period period 6

Block d-block

Element category  transition metal

Electron configuration [Xe] 4f14 5d3 6s2

Electrons per shell

2, 8, 18, 32, 11, 2

Symbol Tb

Naming after Ytterby (Sweden), where it was mined

Discovery and first isolation Carl Gustaf Mosander (1843)

Appearance silvery white

Standard atomic weight Ar, std(Tb) 158.925354(8)

Atomic number (Z) 65

Group group n/a

Period period 6

Block f-block

Element category  lanthanide

Electron configuration [Xe] 4f9 6s2

Electrons per shell

2, 8, 18, 27, 8, 2

Symbol Tc

Prediction Dmitri Mendeleev (1871)

Discovery and first isolation Emilio Segrè and Carlo Perrier (1937)

Appearance shiny gray metal

Mass number [97]

Atomic number (Z) 43

Group group 7

Period period 5

Block d-block

Element category  transition metal

Electron configuration [Kr] 4d5 5s2

Electrons per shell

2, 8, 18, 13, 2

Symbol Te

Naming after Roman Tellus, deity of the Earth

Discovery Franz-Joseph Müller von Reichenstein (1782)

First isolation Martin Heinrich Klaproth

Appearance silvery lustrous gray (crystalline),

brown-black powder (amorphous)

Standard atomic weight Ar, std(Te) 127.60(3)

Atomic number (Z) 52

Group group 16 (chalcogens)

Period period 5

Block p-block

Element category  metalloid

Electron configuration [Kr] 4d10 5s2 5p4

Electrons per shell

2, 8, 18, 18, 6

Symbol Th

Naming after Thor, the Norse god of thunder

Discovery Jöns Jakob Berzelius (1829)

Appearance silvery, often with black tarnish

Standard atomic weight Ar, std(Th) 232.0377(4)

Atomic number (Z) 90

Group group n/a

Period period 7

Block f-block

Element category  actinide

Electron configuration [Rn] 6d2 7s2

Electrons per shell

2, 8, 18, 32, 18, 10, 2

Symbol Ti

Discovery William Gregor (1791)

First isolation Jöns Jakob Berzelius (1825)

Named by Martin Heinrich Klaproth (1795)

Appearance silvery grey-white metallic

Standard atomic weight Ar, std(Ti) 47.867(1)

Atomic number (Z) 22

Group group 4

Period period 4

Block d-block

Element category  transition metal

Electron configuration [Ar] 3d2 4s2

Electrons per shell

2, 8, 10, 2

Symbol Tl

Naming after Greek thallos, green shoot or twig

Discovery William Crookes (1861)

First isolation Claude-Auguste Lamy (1862)

Appearance silvery white

Standard atomic weight Ar, std(Tl) [204.382, 204.385] conventional: 204.38

Atomic number (Z) 81

Group group 13 (boron group)

Period period 6

Block p-block

Element category  post-transition metal

Electron configuration [Xe] 4f14 5d10 6s2 6p1

Electrons per shell

2, 8, 18, 32, 18, 3

Symbol Tm

Naming after Thule, a mythical region in Scandinavia

Discovery and first isolation Per Teodor Cleve (1879)

Appearance silvery gray

Standard atomic weight Ar, std(Tm) 168.934218(6)

Atomic number (Z) 69

Group group n/a

Period period 6

Block f-block

Element category  lanthanide

Electron configuration [Xe] 4f13 6s2

Electrons per shell

2, 8, 18, 31, 8, 2

Symbol Ts

Naming after Tennessee region

Discovery Joint Institute for Nuclear Research, Lawrence Livermore National Laboratory, Vanderbilt University and Oak Ridge National Laboratory (2009)

Appearance semimetallic (predicted)

Mass number [294]

Atomic number (Z) 117

Group group 17

Period period 7

Block p-block

Element category  unknown chemical properties, but probably a post-transition metal[3][4]

Electron configuration [Rn] 5f14 6d10 7s2 7p5 (predicted)[5]

Electrons per shell

2, 8, 18, 32, 32, 18, 7 (predicted)

Symbol U

Naming after planet Uranus, itself named after Greek god of the sky Uranus

Discovery Martin Heinrich Klaproth (1789)

First isolation Eugène-Melchior Péligot (1841)

Appearance silvery gray metallic; corrodes to a spalling black oxide coat in air

Standard atomic weight Ar, std(U) 238.02891(3)

Atomic number (Z) 92

Group group n/a

Period period 7

Block f-block

Element category  actinide

Electron configuration [Rn] 5f3 6d1 7s2

Electrons per shell

2, 8, 18, 32, 21, 9, 2

Symbol V

Discovery Andrés Manuel del Río (1801)

First isolation Nils Gabriel Sefström (1830)

Named by Nils Gabriel Sefström (1830)

Appearance blue-silver-grey metal

Standard atomic weight Ar, std(V) 50.9415(1)

Atomic number (Z) 23

Group group 5

Period period 4

Block d-block

Element category  transition metal

Electron configuration [Ar] 3d3 4s2

Electrons per shell

2, 8, 11, 2

Symbol W

Discovery Carl Wilhelm Scheele (1781)

First isolation Juan José Elhuyar and Fausto Elhuyar (1783)

Named by Torbern Bergman (1781)

Appearance grayish white, lustrous

Standard atomic weight Ar, std(W) 183.84(1)

Atomic number (Z) 74

Group group 6

Period period 6

Block d-block

Element category  transition metal

Electron configuration [Xe] 4f14 5d4 6s2[2]

Electrons per shell

2, 8, 18, 32, 12, 2

Symbol Xe

Discovery and first isolation William Ramsay and Morris Travers (1898)

Appearance colorless gas, exhibiting a blue glow when placed in an electric field

Standard atomic weight Ar, std(Xe) 131.293(6)

Atomic number (Z) 54

Group group 18 (noble gases)

Period period 5

Block p-block

Element category  noble gas

Electron configuration [Kr] 4d10 5s2 5p6

Electrons per shell

2, 8, 18, 18, 8

Symbol Y

Naming after Ytterby (Sweden) and its mineral ytterbite (gadolinite)

Discovery Johan Gadolin (1794)

First isolation Heinrich Rose (1843)

Appearance silvery white

Standard atomic weight Ar, std(Y) 88.90584(1)

Atomic number (Z) 39

Group group 3

Period period 5

Block d-block

Element category  Transition metal

Electron configuration [Kr] 4d1 5s2

Electrons per shell

2, 8, 18, 9, 2

Symbol Yb

Naming after Ytterby (Sweden), where it was mined

Discovery Jean Charles Galissard de Marignac (1878)

First isolation Carl Auer von Welsbach (1906)

Appearance silvery white; with a pale yellow tint

Standard atomic weight Ar, std(Yb) 173.045(10)

Atomic number (Z) 70

Group group n/a

Period period 6

Block f-block

Element category  lanthanide

Electron configuration [Xe] 4f14 6s2

Electrons per shell

2, 8, 18, 32, 8, 2

Symbol Zn

Discovery Indian metallurgists (before 1000 BCE)

First isolation Andreas Sigismund Marggraf (1746)

Recognized as a unique metal by Rasaratna Samuccaya (800)

Appearance silver-gray

Standard atomic weight Ar, std(Zn) 65.38(2)

Atomic number (Z) 30

Group group 12

Period period 4

Block d-block

Element category  post-transition metal, alternatively considered a transition metal

Electron configuration [Ar] 3d10 4s2

Electrons per shell

2, 8, 18, 2

Symbol Zr

Naming after zircon, zargun زرگون meaning "gold-colored".

Discovery Martin Heinrich Klaproth (1789)

First isolation Jöns Jakob Berzelius (1824)

Appearance silvery white

Standard atomic weight Ar, std(Zr) 91.224(2)

Atomic number (Z) 40

Group group 4

Period period 5

Block d-block

Element category  transition metal

Electron configuration [Kr] 4d2 5s2

Electrons per shell

2, 8, 18, 10, 2