transuranium elements, in chemistry, radioactive elements with atomic numbers greater than that of uranium (at. no. 92). All the transuranium elements of the actinide series were discovered as synthetic radioactive isotopes at the Univ. of California at Berkeley or at Argonne National Laboratory; in order of increasing atomic number they are neptunium, plutonium, americium, curium, berkelium, californium, einsteinium, fermium, mendelevium, nobelium, and lawrencium. Of these only neptunium and plutonium occur in nature; they are produced in minute amounts in the radioactive decay of uranium.

Much of the study of the transuranium elements has taken place at the Lawrence Berkeley National Laboratory (at Berkeley, Calif.) and at the Joint Institute for Nuclear Research in Dubna, Russia; workers at both locations share credit for the independent discovery of rutherfordium, dubnium, and seaborgium (at. no. 104, 105, and 106, respectively), which are the first three transactinide elements. A German team at the Institute for Heavy Ion Research at Darmstadt discovered bohrium, hassium, meitnerium, darmstadtium, roentgenium, and ununbium (at. no. 107 through 112). The Dubna laboratory, with assistance from Berkeley, claims to have synthesized ununquadium (at. no. 114), and working jointly with the Lawrence Livermore National Laboratory (at Livermore, Calif.) claims to have produced ununtrium (at. no. 113) and ununpentium (at. no. 115). The Berkeley team claimed to have produced ununhexium (at. no. 116) and ununoctium (at. no. 118), but later retracted the claim for ununoctium after other laboratories failed to reproduce Berkeley's results and a reanalysis of their data did not show the production of the element. Other research teams have since synthesized ununhexium directly.

Up to and including fermium (at. no. 100), the transuranium elements are produced by the capture of neutrons; the transfermium elements are synthesized by the bombardment of transuranium targets with light particles or, more recently, by projecting medium-weight elements at targets of other medium-weight elements (see also synthetic elements).

Isotopes of the transuranium elements are radioactive because their large nuclei are unstable, and the transactinide, or superheavy, elements in particular have very short half-lives. However, on the basis of theories of nuclear structure, physicists have predicted that certain transactinide elements may have relatively stable isotopes. For example, an isotope of element 114 with mass number 298 (comprising 114 protons and 184 neutrons) should be very stable and resemble lead in its chemical properties. However, the three isotopes of element 114 that are claimed to have been synthesized have fewer than the requisite 184 neutrons.

transmutation of elements, conversion of one chemical element into another. The expression has both historical and contemporary significance. The transmutation of certain metals into gold by means of a substance called the philosopher's stone was one of the two most ambitious quests of the alchemists (see alchemy); the other was for the elixir of life that would cure all diseases, restore youth to the aged, and make youthfulness eternal. The possibility of finding the philosopher's stone harmonized with ideas long generally held, and honest and able men were hopeful of finding it. Now and then a charlatan professed to have found it. In modern times it has been found that a transmutation from one element to another actually does occur in the process of natural radioactivity. Transmutation of elements can be achieved artificially by the bombardment of elements with high-speed particles by means of such machines as the cyclotron (see particle accelerator). Both artificial and natural transmutations involve changing the number of protons in the atomic nucleus. The transuranium elements are created in this manner. When a nucleus is bombarded with neutrons from an atomic pile or nuclear reactor, some of the neutrons will be absorbed, resulting in an unstable nucleus. The nucleus then becomes more stable by converting one of its neutrons into a proton by beta decay, becoming a nucleus of the next heavier element in the process.

transition elements or transition metals, in chemistry, group of elements characterized by the filling of an inner d electron orbital as atomic number increases. This includes the elements from titanium to copper, and those lying in the columns below them in the periodic table. Many of the chemical and physical properties of the transition elements are due to their unfilled d orbitals. In the elements of the lanthanide series and the actinide series the inner f orbital is filled as atomic number increases; those elements are often called the inner transition elements. Transition elements generally exhibit high density, high melting point, magnetic properties, variable valence, and the formation of stable coordination complexes. Their variable valence is due to the electrons in the d orbitals. The study of the complex ions and compounds formed by transition metals is an important branch of chemistry. Many of these complexes are highly colored and exhibit paramagnetism.

transactinide elements, in chemistry, elements with atomic numbers greater than that of lawrencium (at. no. 103), the last member of the actinide series. See transuranium elements.

synthetic elements, in chemistry, radioactive elements that were not discovered occurring in nature but as artificially produced isotopes. They are technetium (at. no. 43), which was the first element to be synthesized, promethium (at. no. 61), astatine (at. no. 85), francium (at. no. 87), and the transuranium elements (at. no. 93 and beyond in the periodic table). Some of these elements have since been shown to exist in minute amounts in nature, usually as short-lived members of natural radioactive decay series (see radioactivity).

The synthetic elements through at. no. 100 (fermium) are created by bombarding a heavy element, such as uranium or plutonium, with neutrons or alpha particles. The synthesis of the transfermium elements (elements with at. no. 101 or greater) is accomplished by the fusion of the nuclei of two lighter elements. Elements 101 through 106 were first produced by fusing the nuclei of slightly lighter elements, such as californium, with those of light elements, such as carbon. Elements 107 through 112 were first produced by fusing the nuclei of medium-weight elements, such as bismuth or lead, with those of other medium-weight elements, such as iron, nickel, or zinc. Element 114 was first produced by fusing the nuclei of plutonium and calcium and subsequently by fusing the nuclei of lead and krypton, as was element 116. Element 115 was produced by bombarding americium with calcium, and element 113 resulted from the radioactive decay of element 115. The claim by Lawrence Berkeley National Laboratory to have created element 118 has been retracted.)

The transfermium elements are produced in very small quantities (one atom at a time), and identification is therefore very difficult because of half-lives ranging from minutes to milliseconds and the need to identify the products by methods other than known chemical separations. This has led to controversy over reported discoveries and over the naming of the elements. It has been predicted that one isotope of element 114—containing 114 protons and 184 neutrons—would be very stable because its nucleus would have a full complement of protons and neutrons. Termed an "island of stability," its half-life might be measured in years. However, none of the three isotopes of element 114 synthesized as yet have as many as 184 neutrons, and their half-lives are still in the millisecond range.

man-made elements: see synthetic elements.

artificial elements: see synthetic elements.

Atomic Number:	Atomic Number: 40
Atomic Symbol:	Atomic Symbol: Zr
	Name of Element: Zirconium
Atomic Weight:	Atomic Weight: 91.22
Electron Configuration:	Electron Configuration: 2 · 8 · 1810 · 2

Atomic Number:	Atomic Number: 30
Atomic Symbol:	Atomic Symbol: Zn
	Name of Element: Zinc
Atomic Weight:	Atomic Weight: 65.38
Electron Configuration:	Electron Configuration: 2 · 8 · 18 · 2

Atomic Number:	Atomic Number: 39
Atomic Symbol:	Atomic Symbol: Y
	Name of Element: Yttrium
Atomic Weight:	Atomic Weight: 88.9059
Electron Configuration:	Electron Configuration: 2 · 8 · 189 · 2

Atomic Number:	Atomic Number: 70
Atomic Symbol:	Atomic Symbol: Yb
	Name of Element: Ytterbium
Atomic Weight:	Atomic Weight: 173.04
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 8 · 2

Atomic Number:	Atomic Number: 54
Atomic Symbol:	Atomic Symbol: Xe
	Name of Element: Xenon
Atomic Weight:	Atomic Weight: 131.29
Electron Configuration:	Electron Configuration: 2 · 8 · 1818 · 8

Atomic Number:	Atomic Number: 23
Atomic Symbol:	Atomic Symbol: V
	Name of Element: Vanadium
Atomic Weight:	Atomic Weight: 50.9415
Electron Configuration:	Electron Configuration: 2 · 8 · 11 · 2

Atomic Number:	Atomic Number: 92
Atomic Symbol:	Atomic Symbol: U
	Name of Element: Uranium
Atomic Weight:	Atomic Weight: 238.0289
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 219 · 2

Atomic Number:	Atomic Number: 113
Atomic Symbol:	Atomic Symbol: Uut
	Name of Element: Ununtrium
Atomic Weight:	Atomic Weight: (284)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 3218 · 6

Atomic Number:	Atomic Number: 114
Atomic Symbol:	Atomic Symbol: Uuq
	Name of Element: Ununquadium
Atomic Weight:	Atomic Weight: (289)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 3218 · 4

Atomic Number:	Atomic Number: 115
Atomic Symbol:	Atomic Symbol: Uup
	Name of Element: Ununpentium
Atomic Weight:	Atomic Weight: (288)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 3218 · 6

Atomic Number:	Atomic Number: 118
Atomic Symbol:	Atomic Symbol: Uuo
	Name of Element: Ununoctium
Atomic Weight:	Atomic Weight: (294)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 3218 · 8

Atomic Number:	Atomic Number: 116
Atomic Symbol:	Atomic Symbol: Uuh
	Name of Element: Ununhexium
Atomic Weight:	Atomic Weight: (292)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 3218 · 6

Atomic Number:	Atomic Number: 112
Atomic Symbol:	Atomic Symbol: Uub
	Name of Element: Ununbium
Atomic Weight:	Atomic Weight: (285)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 3218 · 2

Atomic Number:	Atomic Number: 74
Atomic Symbol:	Atomic Symbol: W
	Name of Element: Tungsten
Atomic Weight:	Atomic Weight: 183.85
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 12 · 2

Atomic Number:	Atomic Number: 22
Atomic Symbol:	Atomic Symbol: Ti
	Name of Element: Titanium
Atomic Weight:	Atomic Weight: 47.88
Electron Configuration:	Electron Configuration: 2 · 8 · 10 · 2

Atomic Number:	Atomic Number: 50
Atomic Symbol:	Atomic Symbol: Sn
	Name of Element: Tin
Atomic Weight:	Atomic Weight: 118.69
Electron Configuration:	Electron Configuration: 2 · 8 · 1818 · 4

Atomic Number:	Atomic Number: 69
Atomic Symbol:	Atomic Symbol: Tm
	Name of Element: Thulium
Atomic Weight:	Atomic Weight: 168.9342
Electron Configuration:	Electron Configuration: 2 · 8 · 1831 · 8 · 2

Atomic Number:	Atomic Number: 90
Atomic Symbol:	Atomic Symbol: Th
	Name of Element: Thorium
Atomic Weight:	Atomic Weight: 232.0381
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 1810 · 2

Atomic Number:	Atomic Number: 81
Atomic Symbol:	Atomic Symbol: Tl
	Name of Element: Thallium
Atomic Weight:	Atomic Weight: 204.383
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 18 · 3

Atomic Number:	Atomic Number: 65
Atomic Symbol:	Atomic Symbol: Tb
	Name of Element: Terbium
Atomic Weight:	Atomic Weight: 158.9254
Electron Configuration:	Electron Configuration: 2 · 8 · 1827 · 8 · 2

Atomic Number:	Atomic Number: 52
Atomic Symbol:	Atomic Symbol: Te
	Name of Element: Tellurium
Atomic Weight:	Atomic Weight: 127.60
Electron Configuration:	Electron Configuration: 2 · 8 · 1818 · 6

Atomic Number:	Atomic Number: 43
Atomic Symbol:	Atomic Symbol: Tc
	Name of Element: Technetium
Atomic Weight:	Atomic Weight: (98)
Electron Configuration:	Electron Configuration: 2 · 8 · 1813 · 2

Atomic Number:	Atomic Number: 73
Atomic Symbol:	Atomic Symbol: Ta
	Name of Element: Tantalum
Atomic Weight:	Atomic Weight: 180.9479
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 11 · 2

Atomic Number:	Atomic Number: 16
Atomic Symbol:	Atomic Symbol: S
	Name of Element: Sulfur
Atomic Weight:	Atomic Weight: 32.06
Electron Configuration:	Electron Configuration: 2 · 8 · 6

Atomic Number:	Atomic Number: 38
Atomic Symbol:	Atomic Symbol: Sr
	Name of Element: Strontium
Atomic Weight:	Atomic Weight: 87.62
Electron Configuration:	Electron Configuration: 2 · 8 · 188 · 2

Atomic Number:	Atomic Number: 11
Atomic Symbol:	Atomic Symbol: Na
	Name of Element: Sodium
Atomic Weight:	Atomic Weight: 22.98977
Electron Configuration:	Electron Configuration: 2 · 8 · 1

Atomic Number:	Atomic Number: 47
Atomic Symbol:	Atomic Symbol: Ag
	Name of Element: Silver
Atomic Weight:	Atomic Weight: 107.8682
Electron Configuration:	Electron Configuration: 2 · 8 · 1818 · 1

Atomic Number:	Atomic Number: 14
Atomic Symbol:	Atomic Symbol: Si
	Name of Element: Silicon
Atomic Weight:	Atomic Weight: 28.0855
Electron Configuration:	Electron Configuration: 2 · 8 · 4

Atomic Number:	Atomic Number: 34
Atomic Symbol:	Atomic Symbol: Se
	Name of Element: Selenium
Atomic Weight:	Atomic Weight: 78.96
Electron Configuration:	Electron Configuration: 2 · 8 · 18 · 6

Atomic Number:	Atomic Number: 106
Atomic Symbol:	Atomic Symbol: Sg
	Name of Element: Seaborgium
Atomic Weight:	Atomic Weight: (266)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 3212 · 2

Atomic Number:	Atomic Number: 21
Atomic Symbol:	Atomic Symbol: Sc
	Name of Element: Scandium
Atomic Weight:	Atomic Weight: 44.9559
Electron Configuration:	Electron Configuration: 2 · 8 · 9 · 2

Atomic Number:	Atomic Number: 62
Atomic Symbol:	Atomic Symbol: Sm
	Name of Element: Samarium
Atomic Weight:	Atomic Weight: 150.36
Electron Configuration:	Electron Configuration: 2 · 8 · 1824 · 8 · 2

Atomic Number:	Atomic Number: 104
Atomic Symbol:	Atomic Symbol: Rf
	Name of Element: Rutherfordium
Atomic Weight:	Atomic Weight: (261)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 3210 · 2

Atomic Number:	Atomic Number: 44
Atomic Symbol:	Atomic Symbol: Ru
	Name of Element: Ruthenium
Atomic Weight:	Atomic Weight: 101.07
Electron Configuration:	Electron Configuration: 2 · 8 · 1815 · 1

Atomic Number:	Atomic Number: 37
Atomic Symbol:	Atomic Symbol: Rb
	Name of Element: Rubidium
Atomic Weight:	Atomic Weight: 85.4678
Electron Configuration:	Electron Configuration: 2 · 8 · 188 · 1

Atomic Number:	Atomic Number: 111
Atomic Symbol:	Atomic Symbol: Rg
	Name of Element: Roentgenium
Atomic Weight:	Atomic Weight: (272)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 3218 · 1

Atomic Number:	Atomic Number: 45
Atomic Symbol:	Atomic Symbol: Rh
	Name of Element: Rhodium
Atomic Weight:	Atomic Weight: 102.9055
Electron Configuration:	Electron Configuration: 2 · 8 · 1816 · 1

Atomic Number:	Atomic Number: 75
Atomic Symbol:	Atomic Symbol: Re
	Name of Element: Rhenium
Atomic Weight:	Atomic Weight: 186.207
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 13 · 2

Atomic Number:	Atomic Number: 86
Atomic Symbol:	Atomic Symbol: Rn
	Name of Element: Radon
Atomic Weight:	Atomic Weight: (222)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 18 · 8

Atomic Number:	Atomic Number: 88
Atomic Symbol:	Atomic Symbol: Ra
	Name of Element: Radium
Atomic Weight:	Atomic Weight: 226.0254
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 188 · 2

Atomic Number:	Atomic Number: 91
Atomic Symbol:	Atomic Symbol: Pa
	Name of Element: Protactinium
Atomic Weight:	Atomic Weight: 231.0359
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 209 · 2

Atomic Number:	Atomic Number: 61
Atomic Symbol:	Atomic Symbol: Pm
	Name of Element: Promethium
Atomic Weight:	Atomic Weight: (145)
Electron Configuration:	Electron Configuration: 2 · 8 · 1823 · 8 · 2

Atomic Number:	Atomic Number: 59
Atomic Symbol:	Atomic Symbol: Pr
	Name of Element: Praseodymium
Atomic Weight:	Atomic Weight: 140.9077
Electron Configuration:	Electron Configuration: 2 · 8 · 1821 · 8 · 2

Atomic Number:	Atomic Number: 19
Atomic Symbol:	Atomic Symbol: K
	Name of Element: Potassium
Atomic Weight:	Atomic Weight: 39.0983
Electron Configuration:	Electron Configuration: 2 · 8 · 8 · 1

Atomic Number:	Atomic Number: 84
Atomic Symbol:	Atomic Symbol: Po
	Name of Element: Polonium
Atomic Weight:	Atomic Weight: (209)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 18 · 6

Atomic Number:	Atomic Number: 94
Atomic Symbol:	Atomic Symbol: Pu
	Name of Element: Plutonium
Atomic Weight:	Atomic Weight: (244)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 248 · 2

Atomic Number:	Atomic Number: 78
Atomic Symbol:	Atomic Symbol: Pt
	Name of Element: Platinum
Atomic Weight:	Atomic Weight: 195.08
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 16 · 2

Atomic Number:	Atomic Number: 15
Atomic Symbol:	Atomic Symbol: P
	Name of Element: Phosphorus
Atomic Weight:	Atomic Weight: 30.97376
Electron Configuration:	Electron Configuration: 2 · 8 · 5

Atomic Number:	Atomic Number: 46
Atomic Symbol:	Atomic Symbol: Pd
	Name of Element: Palladium
Atomic Weight:	Atomic Weight: 106.42
Electron Configuration:	Electron Configuration: 2 · 8 · 1818 · 0

Atomic Number:	Atomic Number: 8
Atomic Symbol:	Atomic Symbol: O
	Name of Element: Oxygen
Atomic Weight:	Atomic Weight: 15.9994
Electron Configuration:	Electron Configuration: 2 · 6

Atomic Number:	Atomic Number: 76
Atomic Symbol:	Atomic Symbol: Os
	Name of Element: Osmium
Atomic Weight:	Atomic Weight: 190.2
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 14 · 2

Atomic Number:	Atomic Number: 102
Atomic Symbol:	Atomic Symbol: No
	Name of Element: Nobelium
Atomic Weight:	Atomic Weight: (259)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 328 · 2

Atomic Number:	Atomic Number: 7
Atomic Symbol:	Atomic Symbol: N
	Name of Element: Nitrogen
Atomic Weight:	Atomic Weight: 14.0067
Electron Configuration:	Electron Configuration: 2 · 5

Atomic Number:	Atomic Number: 41
Atomic Symbol:	Atomic Symbol: Nb
	Name of Element: Niobium
Atomic Weight:	Atomic Weight: 92.9064
Electron Configuration:	Electron Configuration: 2 · 8 · 1812 · 1

Atomic Number:	Atomic Number: 28
Atomic Symbol:	Atomic Symbol: Ni
	Name of Element: Nickel
Atomic Weight:	Atomic Weight: 58.69
Electron Configuration:	Electron Configuration: 2 · 8 · 16 · 2

Atomic Number:	Atomic Number: 93
Atomic Symbol:	Atomic Symbol: Np
	Name of Element: Neptunium
Atomic Weight:	Atomic Weight: 237.0482
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 229 · 2

Atomic Number:	Atomic Number: 10
Atomic Symbol:	Atomic Symbol: Ne
	Name of Element: Neon
Atomic Weight:	Atomic Weight: 20.179
Electron Configuration:	Electron Configuration: 2 · 8

Atomic Number:	Atomic Number: 60
Atomic Symbol:	Atomic Symbol: Nd
	Name of Element: Neodymium
Atomic Weight:	Atomic Weight: 144.24
Electron Configuration:	Electron Configuration: 2 · 8 · 1822 · 8 · 2

Atomic Number:	Atomic Number: 42
Atomic Symbol:	Atomic Symbol: Mo
	Name of Element: Molybdenum
Atomic Weight:	Atomic Weight: 95.94
Electron Configuration:	Electron Configuration: 2 · 8 · 1813 · 1

Atomic Number:	Atomic Number: 80
Atomic Symbol:	Atomic Symbol: Hg
	Name of Element: Mercury
Atomic Weight:	Atomic Weight: 200.59
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 18 · 2

Atomic Number:	Atomic Number: 101
Atomic Symbol:	Atomic Symbol: Md
	Name of Element: Mendelevium
Atomic Weight:	Atomic Weight: (258)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 318 · 2

Atomic Number:	Atomic Number: 109
Atomic Symbol:	Atomic Symbol: Mt
	Name of Element: Meitnerium
Atomic Weight:	Atomic Weight: (266)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 3215 · 2

Atomic Number:	Atomic Number: 25
Atomic Symbol:	Atomic Symbol: Mn
	Name of Element: Manganese
Atomic Weight:	Atomic Weight: 54.9380
Electron Configuration:	Electron Configuration: 2 · 8 · 13 · 2

Atomic Number:	Atomic Number: 12
Atomic Symbol:	Atomic Symbol: Mg
	Name of Element: Magnesium
Atomic Weight:	Atomic Weight: 24.305
Electron Configuration:	Electron Configuration: 2 · 8 · 2

Atomic Number:	Atomic Number: 71
Atomic Symbol:	Atomic Symbol: Lu
	Name of Element: Lutetium
Atomic Weight:	Atomic Weight: 174.967
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 9 · 2

Atomic Number:	Atomic Number: 3
Atomic Symbol:	Atomic Symbol: Li
	Name of Element: Lithium
Atomic Weight:	Atomic Weight: 6.941
Electron Configuration:	Electron Configuration: 2 · 1

Atomic Number:	Atomic Number: 82
Atomic Symbol:	Atomic Symbol: Pb
	Name of Element: Lead
Atomic Weight:	Atomic Weight: 207.2
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 18 · 4

Atomic Number:	Atomic Number: 103
Atomic Symbol:	Atomic Symbol: Lr
	Name of Element: Lawrencium
Atomic Weight:	Atomic Weight: (262)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 329 · 2

Atomic Number:	Atomic Number: 57
Atomic Symbol:	Atomic Symbol: La
	Name of Element: Lanthanum
Atomic Weight:	Atomic Weight: 138.9055
Electron Configuration:	Electron Configuration: 2 · 8 · 1818 · 9 · 2

Atomic Number:	Atomic Number: 36
Atomic Symbol:	Atomic Symbol: Kr
	Name of Element: Krypton
Atomic Weight:	Atomic Weight: 83.80
Electron Configuration:	Electron Configuration: 2 · 8 · 18 · 8

Atomic Number:	Atomic Number: 26
Atomic Symbol:	Atomic Symbol: Fe
	Name of Element: Iron
Atomic Weight:	Atomic Weight: 55.845
Electron Configuration:	Electron Configuration: 2 · 8 · 14 · 2

Atomic Number:	Atomic Number: 77
Atomic Symbol:	Atomic Symbol: Ir
	Name of Element: Iridium
Atomic Weight:	Atomic Weight: 192.22
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 15 · 2

Atomic Number:	Atomic Number: 53
Atomic Symbol:	Atomic Symbol: I
	Name of Element: Iodine
Atomic Weight:	Atomic Weight: 126.9045
Electron Configuration:	Electron Configuration: 2 · 8 · 1818 · 7

Atomic Number:	Atomic Number: 49
Atomic Symbol:	Atomic Symbol: In
	Name of Element: Indium
Atomic Weight:	Atomic Weight: 114.82
Electron Configuration:	Electron Configuration: 2 · 8 · 1818 · 3

Atomic Number:	Atomic Number: 1
Atomic Symbol:	Atomic Symbol: H
	Name of Element: Hydrogen
Atomic Weight:	Atomic Weight: 1.00794
Electron Configuration:	Electron Configuration: 1

Atomic Number:	Atomic Number: 67
Atomic Symbol:	Atomic Symbol: Ho
	Name of Element: Holmium
Atomic Weight:	Atomic Weight: 164.9304
Electron Configuration:	Electron Configuration: 2 · 8 · 1829 · 8 · 2

Atomic Number:	Atomic Number: 2
Atomic Symbol:	Atomic Symbol: He
	Name of Element: Helium
Atomic Weight:	Atomic Weight: 4.0026
Electron Configuration:	Electron Configuration: 2

Atomic Number:	Atomic Number: 108
Atomic Symbol:	Atomic Symbol: Hs
	Name of Element: Hassium
Atomic Weight:	Atomic Weight: (265)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 3214 · 2

Atomic Number:	Atomic Number: 72
Atomic Symbol:	Atomic Symbol: Hf
	Name of Element: Hafnium
Atomic Weight:	Atomic Weight: 178.49
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 10 · 2

Atomic Number:	Atomic Number: 79
Atomic Symbol:	Atomic Symbol: Au
	Name of Element: Gold
Atomic Weight:	Atomic Weight: 196.9665
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 18 · 1

Atomic Number:	Atomic Number: 32
Atomic Symbol:	Atomic Symbol: Ge
	Name of Element: Germanium
Atomic Weight:	Atomic Weight: 72.59
Electron Configuration:	Electron Configuration: 2 · 8 · 18 · 4

Atomic Number:	Atomic Number: 31
Atomic Symbol:	Atomic Symbol: Ga
	Name of Element: Gallium
Atomic Weight:	Atomic Weight: 69.72
Electron Configuration:	Electron Configuration: 2 · 8 · 18 · 3

Atomic Number:	Atomic Number: 64
Atomic Symbol:	Atomic Symbol: Gd
	Name of Element: Gadolinium
Atomic Weight:	Atomic Weight: 157.25
Electron Configuration:	Electron Configuration: 2 · 8 · 1825 · 9 · 2

Atomic Number:	Atomic Number: 87
Atomic Symbol:	Atomic Symbol: Fr
	Name of Element: Francium
Atomic Weight:	Atomic Weight: (223)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 188 · 1

Atomic Number:	Atomic Number: 9
Atomic Symbol:	Atomic Symbol: F
	Name of Element: Fluorine
Atomic Weight:	Atomic Weight: 18.998403
Electron Configuration:	Electron Configuration: 2 · 7

Atomic Number:	Atomic Number: 100
Atomic Symbol:	Atomic Symbol: Fm
	Name of Element: Fermium
Atomic Weight:	Atomic Weight: (257)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 308 · 2

Atomic Number:	Atomic Number: 63
Atomic Symbol:	Atomic Symbol: Eu
	Name of Element: Europium
Atomic Weight:	Atomic Weight: 151.96
Electron Configuration:	Electron Configuration: 2 · 8 · 1825 · 8 · 2

Atomic Number:	Atomic Number: 68
Atomic Symbol:	Atomic Symbol: Er
	Name of Element: Erbium
Atomic Weight:	Atomic Weight: 167.26
Electron Configuration:	Electron Configuration: 2 · 8 · 1830 · 8 · 2

Atomic Number:	Atomic Number: 99
Atomic Symbol:	Atomic Symbol: Es
	Name of Element: Einsteinium
Atomic Weight:	Atomic Weight: (252)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 298 · 2

Atomic Number:	Atomic Number: 66
Atomic Symbol:	Atomic Symbol: Dy
	Name of Element: Dysprosium
Atomic Weight:	Atomic Weight: 162.50
Electron Configuration:	Electron Configuration: 2 · 8 · 1828 · 8 · 2

Atomic Number:	Atomic Number: 105
Atomic Symbol:	Atomic Symbol: Db
	Name of Element: Dubnium
Atomic Weight:	Atomic Weight: (262)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 3211 · 2

Atomic Number:	Atomic Number: 110
Atomic Symbol:	Atomic Symbol: Ds
	Name of Element: Darmstadtium
Atomic Weight:	Atomic Weight: (271)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 3217 · 1

Atomic Number:	Atomic Number: 96
Atomic Symbol:	Atomic Symbol: Cm
	Name of Element: Curium
Atomic Weight:	Atomic Weight: (247)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 259 · 2

Atomic Number:	Atomic Number: 29
Atomic Symbol:	Atomic Symbol: Cu
	Name of Element: Copper
Atomic Weight:	Atomic Weight: 63.546
Electron Configuration:	Electron Configuration: 2 · 8 · 18 · 1

Atomic Number:	Atomic Number: 27
Atomic Symbol:	Atomic Symbol: Co
	Name of Element: Cobalt
Atomic Weight:	Atomic Weight: 58.9332
Electron Configuration:	Electron Configuration: 2 · 8 · 15 · 2

Atomic Number:	Atomic Number: 24
Atomic Symbol:	Atomic Symbol: Cr
	Name of Element: Chromium
Atomic Weight:	Atomic Weight: 51.996
Electron Configuration:	Electron Configuration: 2 · 8 · 13 · 1

Atomic Number:	Atomic Number: 17
Atomic Symbol:	Atomic Symbol: Cl
	Name of Element: Chlorine
Atomic Weight:	Atomic Weight: 35.453
Electron Configuration:	Electron Configuration: 2 · 8 · 7

Atomic Number:	Atomic Number: 55
Atomic Symbol:	Atomic Symbol: Cs
	Name of Element: Cesium
Atomic Weight:	Atomic Weight: 132.9054
Electron Configuration:	Electron Configuration: 2 · 8 · 1818 · 8 · 1

Atomic Number:	Atomic Number: 58
Atomic Symbol:	Atomic Symbol: Ce
	Name of Element: Cerium
Atomic Weight:	Atomic Weight: 140.12
Electron Configuration:	Electron Configuration: 2 · 8 · 1820 · 8 · 2

Atomic Number:	Atomic Number: 6
Atomic Symbol:	Atomic Symbol: C
	Name of Element: Carbon
Atomic Weight:	Atomic Weight: 12.011
Electron Configuration:	Electron Configuration: 2 · 4

Atomic Number:	Atomic Number: 98
Atomic Symbol:	Atomic Symbol: Cf
	Name of Element: Californium
Atomic Weight:	Atomic Weight: (251)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 288 · 2

Atomic Number:	Atomic Number: 20
Atomic Symbol:	Atomic Symbol: Ca
	Name of Element: Calcium
Atomic Weight:	Atomic Weight: 40.08
Electron Configuration:	Electron Configuration: 2 · 8 · 8 · 2

Atomic Number:	Atomic Number: 48
Atomic Symbol:	Atomic Symbol: Cd
	Name of Element: Cadmium
Atomic Weight:	Atomic Weight: 112.41
Electron Configuration:	Electron Configuration: 2 · 8 · 1818 · 2

Atomic Number:	Atomic Number: 35
Atomic Symbol:	Atomic Symbol: Br
	Name of Element: Bromine
Atomic Weight:	Atomic Weight: 79.904
Electron Configuration:	Electron Configuration: 2 · 8 · 18 · 7

Atomic Number:	Atomic Number: 5
Atomic Symbol:	Atomic Symbol: B
	Name of Element: Boron
Atomic Weight:	Atomic Weight: 10.81
Electron Configuration:	Electron Configuration: 2 · 3

Atomic Number:	Atomic Number: 107
Atomic Symbol:	Atomic Symbol: Bh
	Name of Element: Bohrium
Atomic Weight:	Atomic Weight: (262)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 3213 · 2

Atomic Number:	Atomic Number: 83
Atomic Symbol:	Atomic Symbol: Bi
	Name of Element: Bismuth
Atomic Weight:	Atomic Weight: 208.9804
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 18 · 5

Atomic Number:	Atomic Number: 4
Atomic Symbol:	Atomic Symbol: Be
	Name of Element: Beryllium
Atomic Weight:	Atomic Weight: 9.01218
Electron Configuration:	Electron Configuration: 2 · 2

Atomic Number:	Atomic Number: 97
Atomic Symbol:	Atomic Symbol: Bk
	Name of Element: Berkelium
Atomic Weight:	Atomic Weight: (247)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 278 · 2

Atomic Number:	Atomic Number: 56
Atomic Symbol:	Atomic Symbol: Ba
	Name of Element: Barium
Atomic Weight:	Atomic Weight: 137.33
Electron Configuration:	Electron Configuration: 2 · 8 · 1818 · 8 · 2

Atomic Number:	Atomic Number: 85
Atomic Symbol:	Atomic Symbol: At
	Name of Element: Astatine
Atomic Weight:	Atomic Weight: (210)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 18 · 7

Atomic Number:	Atomic Number: 33
Atomic Symbol:	Atomic Symbol: As
	Name of Element: Arsenic
Atomic Weight:	Atomic Weight: 74.9216
Electron Configuration:	Electron Configuration: 2 · 8 · 18 · 5

Atomic Number:	Atomic Number: 18
Atomic Symbol:	Atomic Symbol: Ar
	Name of Element: Argon
Atomic Weight:	Atomic Weight: 39.948
Electron Configuration:	Electron Configuration: 2 · 8 · 8

Atomic Number:	Atomic Number: 51
Atomic Symbol:	Atomic Symbol: Sb
	Name of Element: Antimony
Atomic Weight:	Atomic Weight: 121.75
Electron Configuration:	Electron Configuration: 2 · 8 · 1818 · 5

Atomic Number:	Atomic Number: 95
Atomic Symbol:	Atomic Symbol: Am
	Name of Element: Americium
Atomic Weight:	Atomic Weight: (243)
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 258 · 2

Atomic Number:	Atomic Number: 13
Atomic Symbol:	Atomic Symbol: Al
	Name of Element: Aluminum
Atomic Weight:	Atomic Weight: 26.98154
Electron Configuration:	Electron Configuration: 2 · 8 · 3

Atomic Number:	Atomic Number: 89
Atomic Symbol:	Atomic Symbol: Ac
	Name of Element: Actinium
Atomic Weight:	Atomic Weight: 227.0278
Electron Configuration:	Electron Configuration: 2 · 8 · 1832 · 189 · 2

(showing atomic number and atomic symbol; click on atomic symbol for more detailed information)

Groups
1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18
1 H																	2 He
3 Li	4 Be											5 B	6 C	7 N	8 O	9 F	10 Ne
11 Na	12 Mg											13 Al	14 Si	15 P	16 S	17 Cl	18 Ar
19 K	20 Ca	21 Sc	22 Ti	23 V	24 Cr	25 Mn	26 Fe	27 Co	28 Ni	29 Cu	30 Zn	31 Ga	32 Ge	33 As	34 Se	35 Br	36 Kr
37 Rb	38 Sr	39 Y	40 Zr	41 Nb	42 Mo	43 Tc	44 Ru	45 Rh	46 Pd	47 Ag	48 Cd	49 In	50 Sn	51 Sb	52 Te	53 I	54 Xe
55 Cs	56 Ba	57-71 Lanthanide Series	72 Hf	73 Ta	74 W	75 Re	76 Os	77 Ir	78 Pt	79 Au	80 Hg	81 Tl	82 Pb	83 Bi	84 Po	85 At	86 Rn
87 Fr	88 Ra	89-103 Actinide Series	104 Rf	105 Db	106 Sg	107 Bh	108 Hs	109 Mt	110 Ds	111 Rg	112 Uub	113 Uut	114 Uuq	115 Uup	116 Uuh		118 Uuo

Lanthanide Series
(Rare Earth Elements)

57 La

58 Ce

59 Pr

60 Nd

61 Pm

62 Sm

63 Eu

64 Gd

65 Tb

66 Dy

67 Ho

68 Er

69 Tm

70 Yb

71 Lu

Actinide Series
(Radioactive Rare Earth Elements)

89 Ac

90 Th

91 Pa

92 U

93 Np

94 Pu

95 Am

96 Cm

97 Bk

98 Cf

99 Es

100 Fm

101 Md

102 No

103 Lr

Element	Symbol	Atomic Number	Atomic Weight1	Melting Point (Degrees Celsius)	Boiling Point (Degrees Celsius)
actinium	Ac	89	227.0278	1050.	3200. ±300
aluminum	Al	13	26.98154	660.37	2467.
americium	Am	95	(243)	1172.	2600.
antimony	Sb	51	121.75	630.74	1750.
argon	Ar	18	39.948	-189.2	-185.7
arsenic	As	33	74.9216	817. (at 28 atmospheres)	613. (sublimates)
astatine	At	85	(210)	302. (est.)	337. (est.)
barium	Ba	56	137.33	725.	1640.
berkelium	Bk	97	(247)	1050.	2590.
beryllium	Be	4	9.01218	1278. ±5	2970.
bismuth	Bi	83	208.9804	271.3	1560. ±5
bohrium	Bh	107	(262)	—	—
boron	B	5	10.81	2300.	2550. (sublimates)
bromine	Br	35	79.904	-7.2	58.78
cadmium	Cd	48	112.41	320.9	765.
calcium	Ca	20	40.08	839. ±2	1484.
californium	Cf	98	(251)	900.	1470.
carbon	C	6	12.011	∼3550.	4827.
cerium	Ce	58	140.12	799.	3426.
cesium	Cs	55	132.9054	28.40	669.3
chlorine	Cl	17	35.453	-100.98	-34.6
chromium	Cr	24	51.996	1857. ±20	2672.
cobalt	Co	27	58.9332	1495.	2870.
copper	Cu	29	63.546	1083.4 ±0.2	2567.
curium	Cm	96	(247)	1340. ±40	3110.
darmstadtium	Ds	110	(271)	—	—
dubnium	Db	105	(262)	—	—
dysprosium	Dy	66	162.50	1412.	2562.
einsteinium	Es	99	(252)	857.	—
erbium	Er	68	167.26	1529.	2863.
europium	Eu	63	151.96	822.	1597.
fermium	Fm	100	(257)	1527.	—
fluorine	F	9	18.998403	-219.62	-188.14
francium	Fr	87	(223)	(27) (est.)	(677) (est.)
gadolinium	Gd	64	157.25	1313. ±1	3266.
gallium	Ga	31	69.72	29.78	2403.
germanium	Ge	32	72.59	937.4	2830.
gold	Au	79	196.9665	1064.43	2808.
hafnium	Hf	72	178.49	2227. ±20	4602.
hassium	Hs	108	(265)	—	—
helium	He	2	4.0026	>-272.2	-268.934
holmium	Ho	67	164.9304	1474.	2425.
hydrogen	H	1	1.00794	-259.14	-252.87
indium	In	49	114.82	156.61	2080.
iodine	I	53	126.9045	113.5	184.35
iridium	Ir	77	192.22	2410.	4130.
iron	Fe	26	55.845	1535.	2750.
krypton	Kr	36	83.80	-156.6	-152.30 ±0.10
lanthanum	La	57	138.9055	921.	3457.
lawrencium	Lr	103	(262)	1627.	—
lead	Pb	82	207.2	327.502	1740.
lithium	Li	3	6.941	180.54	1342.
lutetium	Lu	71	174.967	1663.	3395.
magnesium	Mg	12	24.305	648.8 ±0.5	1090.
manganese	Mn	25	54.9380	1244. ±3	1962.
meitnerium	Mt	109	(266)	—	—
mendelevium	Md	101	(258)	827.	—
mercury	Hg	80	200.59	-38.842	356.58
molybdenum	Mo	42	95.94	2617.	4612.
neodymium	Nd	60	144.24	1021.	3068.
neon	Ne	10	20.179	-248.67	-246.048
neptunium	Np	93	237.0482	640. ±1	3902. (est.)
nickel	Ni	28	58.69	1453.	2732.
niobium	Nb	41	92.9064	2468. ±10	4742.
nitrogen	N	7	14.0067	-209.86	-195.8
nobelium	No	102	(259)	827.	—
osmium	Os	76	190.2	3045. ±30	5027. ±100
oxygen	O	8	15.9994	-218.4	-182.962
palladium	Pd	46	106.42	1554.	2970.
phosphorus	P	15	30.97376	44.1 (white)	280. (white)
platinum	Pt	78	195.08	1772.	3827. ±100
plutonium	Pu	94	(244)	641.	3232.
polonium	Po	84	(209)	254.	962.
potassium	K	19	39.0983	63.25	760.
praseodymium	Pr	59	140.9077	931.	3512.
promethium	Pm	61	(145)	1042	3000. (est.)
protactinium	Pa	91	231.0359	>1600.	4026.
radium	Ra	88	226.0254	700.	1140.
radon	Rn	86	(222)	-71.	-61.8
rhenium	Re	75	186.207	3180.	5627. (est.)
rhodium	Rh	45	102.9055	1966. ±3	3727. ±100
roentgenium	Rg	111	(272)	—	—
rubidium	Rb	37	85.4678	38.89	686.
ruthenium	Ru	44	101.07	2310.	3900.
rutherfordium	Rf	104	(261)	—	—
samarium	Sm	62	150.36	1072. ±5	1791.
scandium	Sc	21	44.9559	1541.	2831.
seaborgium	Sg	106	(266)	—	—
selenium	Se	34	78.96	217.	684.9 ±1.0
silicon	Si	14	28.0855	1410.	2355.
silver	Ag	47	107.8682	961.93	2212.
sodium	Na	11	22.98977	97.81 ±0.03	882.9
strontium	Sr	38	87.62	269.	1384.
sulfur	S	16	32.06	112.8	444.674
tantalum	Ta	73	180.9479	2996.	5425. ±100
technetium	Tc	43	(98)	2200.	4877.
tellurium	Te	52	127.60	449.5 ±0.3	989.8 ±3.8
terbium	Tb	65	158.9254	1356.	3123.
thallium	Tl	81	204.383	303.5	1457. ±10
thorium	Th	90	232.0381	1750.	∼4790.
thulium	Tm	69	168.9342	1545. ±15	1947.
tin	Sn	50	118.69	231.9681	2270.
titanium	Ti	22	47.88	1660. ±10	3287.
tungsten	W	74	183.85	3410. ±20	5660.
ununbium	Uub	112	(285)	—	—
ununhexium	Uuh	116	(292)	—	—
ununoctium	Uuo	118	(294)	—	—
ununpentium	Uup	115	(288)	—	—
ununquadium	Uuq	114	(289)	—	—
ununtrium	Uut	113	(284)	—	—
uranium	U	92	238.0289	1132.3 ±0.8	3818.
vanadium	V	23	50.9415	1890. ±10	3380.
xenon	Xe	54	131.29	-111.9	-107.1 ±3
ytterbium	Yb	70	173.04	819.	1194.
yttrium	Y	39	88.9059	1522. ±8	3338.
zinc	Zn	30	65.38	419.58	907.
zirconium	Zr	40	91.22	1852. ±2	4377.

1 Parentheses indicate most stable isotope.