Symbol	Pt
Atomic number	78
Group	10 (Nickel group)
Period	6
Block	d
Classification	Transition Metal

Appearance	Silvery white
Color	Gray

Number of protons	78 p+
Number of neutrons	117 n0
Number of electrons	78 e-

From Wikipedia, the free encyclopediaPlatinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, gray-white transition metal. Its name is derived from the Spanish term platina, which is literally translated into "little silver".

Phase at STP	Solid
Density	21.45 g/cm3
Atomic weight	195.085 u

Melting point	2041.4 K 1768.25 °C 3214.85 °F
Boiling point	4098 K 3824.85 °C 6916.73 °F
Heat of vaporization	510.45 kJ/mol

Electronegativity (Pauling Scale)	2.28
Electron affinity	205.041 kJ/mol
Oxidation states	−3, −2, −1, 0, +1, +2, +3, +4, +5, +6 (a mildly basic oxide)
Ionization energies	870 kJ/mol 1791 kJ/mol

Electron configuration Shorthand configuration	[Xe] 4f14 5d9 6s1
Electron configuration Full configuration	1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d9 6s1
Electron configuration chart	1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d9 6s1
Electrons per shell	2, 8, 18, 32, 17, 1
Valence electrons	1
Valency electrons	2,4
Bohr model	Figure: Shell diagram of Platinum (Pt) atom.
Orbital Diagram 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 6s

Discovery

Antonio de Ulloa (1735)

Discovery of platinum Archaeologists have discovered traces of platinum in the gold used in ancient Egyptian burials as early as 1200 BCE. The first European reference to platinum appears in 1557 in the writings of the Italian humanist Julius Caesar Scaliger as a description of an unknown noble metal found between Darién and Mexico, "which no fire nor any Spanish artifice has yet been able to liquefy". In 1735, Antonio de Ulloa and Jorge Juan y Santacilia saw Native Americans mining platinum while the Spaniards were travelling through Colombia and Peru for eight years. Ulloa and Juan found mines with the whitish metal nuggets and took them home to Spain. Antonio de Ulloa returned to Spain and established the first mineralogy lab in Spain and was the first to systematically study platinum, which was in 1748. His historical account of the expedition included a description of platinum as being neither separable nor calcinable. Ulloa also anticipated the discovery of platinum mines. After publishing the report in 1748, Ulloa did not continue to investigate the new metal. In 1752, Henrik Scheffer published a detailed scientific description of the metal, which he referred to as "white gold", including an account of how he succeeded in fusing platinum ore with the aid of arsenic. Scheffer described platinum as being less pliable than gold, but with similar resistance to corrosion.

CAS Number	7440-06-4
ChemSpider ID	22381
EC number	231-116-1
PubChem CID Number	23939