Chromium

Chromium 51.9961(6)   Cr 24 1s22s22p63s23p63d54s1 [ ? ] Transition metal: Properties: Steel-gray, lustrous, hard metal. Malleable and corrosion resistant. Multi-valent. Hazard: Hexavalent chromium is toxic.

Chromium is a chemical element, having the chemical symbol Cr. Its atomic number (the number of protons) is 24. It has a standard atomic weight of 51.9961 g•mol ⁻¹ and is a solid in its elemental form.

Chromium is considered to be a member of the "Transition metal" class of element. At a pressure of 101.325 kPa, it has a boiling point of 2,671 °C, and a melting point of 1,907 °C.