Symbol	Cd
Atomic number	48
Group	12 (Zinc group)
Period	5
Block	d
Classification	Transition Metal

Appearance	Silvery bluish-gray metallic
Color	Silver

Number of protons	48 p+
Number of neutrons	64 n0
Number of electrons	48 e-

From Wikipedia, the free encyclopediaCadmium is 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. Like zinc, it prefers oxidation state +2 in most of its compounds and like mercury it shows a low melting point compared to transition metals.

Phase at STP	Solid
Density	8.65 g/cm3
Atomic weight	112.414 u

Melting point	594.22 K 321.07 °C 609.926 °F
Boiling point	1040 K 766.85 °C 1412.33 °F
Heat of vaporization	99.87 kJ/mol

Electronegativity (Pauling Scale)	1.69
Electron affinity	-68 kJ/mol
Oxidation states	−2, +1, +2 (a mildly basic oxide)
Ionization energies	867.8 kJ/mol 1631.4 kJ/mol 3616 kJ/mol

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

Discovery and first isolation	Karl Samuel Leberecht Hermann, Friedrich Stromeyer, Karl Samuel Leberecht Hermann (1817)
Named by	Friedrich Stromeyer (1817)
Discovery of cadmium Cadmium (Latin cadmia, Greek καδμεία meaning "calamine", a cadmium-bearing mixture of minerals that was named after the Greek mythological character Κάδμος, Cadmus, the founder of Thebes) was discovered in contaminated zinc compounds sold in pharmacies in Germany in 1817 by Friedrich Stromeyer. Karl Samuel Leberecht Hermann simultaneously investigated the discoloration in zinc oxide and found an impurity, first suspected to be arsenic, because of the yellow precipitate with hydrogen sulfide. Additionally Stromeyer discovered that one supplier sold zinc carbonate instead of zinc oxide. Stromeyer found the new element as an impurity in zinc carbonate (calamine), and, for 100 years, Germany remained the only important producer of the metal. The metal was named after the Latin word for calamine, because it was found in this zinc ore. Stromeyer noted that some impure samples of calamine changed color when heated but pure calamine did not. He was persistent in studying these results and eventually isolated cadmium metal by roasting and reducing the sulfide.

CAS Number	7440-43-9
ChemSpider ID	22410
EC number	231-152-8
PubChem CID Number	23973