The chemical symbol for Chromium is Cr and its atomic number is 24.
We find it listed in the periodic table in Group 6 and period 4, and block d.
Chromium belongs to the family of transition metals such as for example the Silver, the Bohrium, cadmium, ...
This element is stable.
Chrome came from the greek work Khroma.
Atomic number (Z) 24
Group, block group 6, d-block
Period: period 4
Element category: transition metal
Standard atomic weight (±) (Ar) 51.9961(6)[1]
Electron configuration: [Ar] 3d5 4s1
per shell: 2, 8, 13, 1
Physical properties
Phase: solid
Melting point: 2180 K (1907 °C, 3465 °F)
Boiling point: 2944 K (2671 °C, 4840 °F)
Density near r.t. : 7.19 g/cm3
when liquid, at m.p. 6.3 g/cm3
Heat of fusion: 21.0 kJ/mol
Heat of vaporization: 347 kJ/mol
Molar heat capacity: 23.35 J/(mol·K)
Atomic properties
Oxidation states: 6, 5, 4, 3, 2, 1, −1, −2, −4 (depending on the oxidation state, an acidic, basic, or amphoteric oxide)
Electronegativity: Pauling scale: 1.66
Ionization energies 1st: 652.9 kJ/mol
2nd: 1590.6 kJ/mol
3rd: 2987 kJ/mol
Atomic radius empirical: 128 pm
Covalent radius: 139±5 pm
Crystal structure: body-centered cubic.
Speed of sound thin rod: 5940 m/s (at 20 °C)
Thermal expansion: 4.9 µm/(m·K) (at 25 °C)
Thermal conductivity: 93.9 W/(m·K)
Electrical resistivity: 125 nΩ·m (at 20 °C)
Magnetic ordering antiferromagnetic (rather: SDW)
Young's modulus: 279 GPa
Shear modulus: 115 GPa
Bulk modulus: 160 GPa
Poisson ratio: 0.21
Vickers hardness: 1060 MPa
Brinell hardness: 687–6500 MPa
CAS Number: 7440-47-3