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Platinum (Pt)

Platinum is a chemical element of the periodic table with chemical symbol Pt and atomic number 78 with an atomic weight of 195.085 u and is classed as transition metal and is part of group 10 (nickel group). Platinum is solid at room temperature.

Platinum in the periodic table

Atomic number78
Group10 (Nickel group)
ClassificationTransition Metal
AppearanceSilvery white
Color Gray
Number of protons78 p+
Number of neutrons117 n0
Number of electrons78 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".

Physical properties

Phase at STPSolid
Density21.45 g/cm3
Atomic weight195.085 u

Thermal properties

Melting point2041.4 K
1768.25 °C
3214.85 °F
Boiling point4098 K
3824.85 °C
6916.73 °F
Heat of vaporization510.45 kJ/mol

Atomic properties

Electronegativity (Pauling Scale)2.28
Electron affinity205.041 kJ/mol
Oxidation states−3, −2, −1, 0, +1, +2, +3, +4, +5, +6
(a mildly basic oxide)
Ionization energies
  1. 870 kJ/mol
  2. 1791 kJ/mol

Electron configuration for platinum

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
Electrons per shell2, 8, 18, 32, 17, 1
Valence electrons 1
Valency electrons 2,4
Bohr model
PlatinumElectron shell for Platinum, created by Injosoft ABPt
Figure: Shell diagram of Platinum (Pt) atom.
Orbital Diagram

The history of Platinum

DiscoveryAntonio 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.


List of unique identifiers for Platinum in various chemical registry databases
CAS Number7440-06-4
ChemSpider ID22381
EC number231-116-1
PubChem CID Number23939