Chromium was discovered by Louis-Nicholas Vauquelin in 1797 while experimenting with a material known as crocoite ore(Siberian red lead).
The name of the element is derived from the Greek word "chroma", meaning color, because many of its compounds are brightly coloured.
Atomic number: 24
Atomic weight: 51.996
Group, period, block: 6, 4, d
Color: silvery metallic
Classification: transition metal
Electron configuration: 4s1 3d5
Density: 7.19 g/cm-3
Melting point: 2180 K, 1907 °C, 3465 °F
Boiling point: 2944 K, 2671 °C, 4840 °F
Oxidation states: 6, 5, 4, 3, 2, 1, -1, -2
Electronegativity: 1.66 (Pauling scale)
Ionization energies: 1st: 652.9 kJ·mol-1
Covalent radius: 139±5 pm
Van der Waals radius: no data
There are four naturally occurring isotopes of chromium exist. They are 50Cr, 52Cr, 53Cr, and 54Cr.