Platinum (Pt)

Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal.

Atomic Number

78

Atomic Mass

195.08 u

Category

transition metal

Phase

solid

Density

21.45 g/cm³

Electron Shells

2, 8, 18, 32, 17, 1

Atomic Structure

Protons: 78 • Electrons: 78 • Neutrons: Varies by isotope

Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s¹ 4f¹⁴ 5d⁹

Discovery

1735 • Antonio de Ulloa