Palladium

Symbol	Pd
Atomic number	46
Group	10 (Nickel group)
Period	5
Block	d
Classification	Transition Metal

Appearance	Silvery white
Color	Silver

Number of protons	46 p+
Number of neutrons	60 n0
Number of electrons	46 e-

From Wikipedia, the free encyclopediaPalladium is 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. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired by her when she slew Pallas.

Phase at STP	Solid
Density	12.023 g/cm3
Atomic weight	106.421 u

Melting point	1828.05 K 1554.9 °C 2830.82 °F
Boiling point	3236 K 2962.85 °C 5365.13 °F
Heat of vaporization	393.3 kJ/mol

Electronegativity (Pauling Scale)	2.2
Electron affinity	54.24 kJ/mol
Oxidation states	0, +1, +2, +3, +4 (a mildly basic oxide)
Ionization energies	804.4 kJ/mol 1870 kJ/mol 3177 kJ/mol

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

Discovery and first isolation

William Hyde Wollaston (1802)

Discovery of palladium William Hyde Wollaston noted the discovery of a new noble metal in July 1802 in his lab book and named it palladium in August of the same year. Wollaston purified a quantity of the material and offered it, without naming the discoverer, in a small shop in Soho in April 1803. After harsh criticism from Richard Chenevix, who claimed that palladium was an alloy of platinum and mercury, Wollaston anonymously offered a reward of £20 for 20 grains of synthetic palladium alloy. Chenevix received the Copley Medal in 1803 after he published his experiments on palladium. Wollaston published the discovery of rhodium in 1804 and mentions some of his work on palladium. He disclosed that he was the discoverer of palladium in a publication in 1805. It was named by Wollaston in 1802 after the asteroid 2 Pallas, which had been discovered two months earlier.

Original word	Pallas
Language of origin	Greek
Name source	Astronomical body
Meaning	“Pallas (asteroid)”
Naming The name comes from the second largest asteroid in the solar system Pallas. The asteroid itself was named after the Greek goddess of wisdom Pallas Athena.

CAS Number	7440-05-3
ChemSpider ID	22380
EC number	231-115-6
PubChem CID Number	23938