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.
Name: Chromium
Symbol: Cr
Atomic number: 24
Atomic weight: 51.996
State: solid
Group, period, block: 6, 4, d
Color: silvery metallic
Classification: transition metal
Electron configuration: 4s1 3d5
2,8,13,1
Physical properties
Density: 7.19 g/cm-3
Melting point: 2180 K, 1907 °C, 3465 °F
Boiling point: 2944 K, 2671 °C, 4840 °F
Atomic properties
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
- Cr
Electron Configuration
Isotopes
There are four naturally occurring isotopes of chromium exist. They are 50Cr, 52Cr, 53Cr, and 54Cr.