Symbol	Tb
Atomic number	65
Group	-
Period	6
Block	f
Classification	Lanthanide

Appearance	Silvery white
Color	Silver

Number of protons	65 p+
Number of neutrons	94 n0
Number of electrons	65 e-

From Wikipedia, the free encyclopediaTerbium is 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. Terbium is never found in nature as a free element, but it is contained in many minerals, including cerite, gadolinite, monazite, xenotime and euxenite.

Phase at STP	Solid
Density	8.23 g/cm3
Atomic weight	158.925 u

Melting point	1629 K 1355.85 °C 2472.53 °F
Boiling point	3396 K 3122.85 °C 5653.13 °F
Heat of vaporization	330.9 kJ/mol

Electronegativity (Pauling Scale)	1.1
Electron affinity	112.4 kJ/mol
Oxidation states	0, +1, +2, +3, +4 (a weakly basic oxide)
Ionization energies	565.8 kJ/mol 1110 kJ/mol 2114 kJ/mol 3839 kJ/mol

Electron configuration Shorthand configuration	[Xe] 4f9 6s2
Electron configuration Full configuration	1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f9 5s2 5p6 6s2
Electron configuration chart	1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f9 5s2 5p6 6s2
Electrons per shell	2, 8, 18, 27, 8, 2
Valence electrons	2
Valency electrons	3
Bohr model	Figure: Shell diagram of Terbium (Tb) atom.
Orbital Diagram 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 6s

Discovery and first isolation	Carl Gustaf Mosander (1843)
Discovery of terbium Swedish chemist Carl Gustaf Mosander discovered terbium as a chemical element in 1843. He detected it as an impurity in yttrium oxide, Y2O3. Yttrium and terbium, as well as erbium and ytterbium, are named after the village of Ytterby in Sweden. Terbium was not isolated in pure form until the advent of ion exchange techniques.

CAS Number	7440-27-9
ChemSpider ID	22397
EC number	231-137-6
PubChem CID Number	23958