Atomic Element Z = 24 • Transition Metal
Chromium (Cr) — Atomic Data, Electron Shells & Reactions
Chromium (symbol Cr, atomic number 24) has a standard atomic weight of 51.996 u and ground-state configuration [Ar] 3d5 4s1.
Atomic Number (Z)
24
IUPAC Symbol
Cr
Standard Atomic Weight
51.996 g/mol
Period / Group / Block
4 / 6 / d-block
Condensed Electron Config
[Ar] 3d5 4s1
Full Subshell Config
1s2 2s2 2p6 3s2 3p6 3d5 4s1
Principal Shell Occupancy
[2, 8, 13, 1]
Pauling Electronegativity
1.66
First Ionization Energy
653 kJ/mol
Covalent Radius
139 pm
Melting Point
2180 K (1906.85 °C)
Boiling Point
2944 K (2670.85 °C)
Density
7.15 g/cm³
Oxidation States
+6, +3, +2
Cr (Z=24) — Valence shell highlighted in vermilion
Interactive Stoichiometry Reactions Involving Chromium:
Cr2O7^2- + Fe^2+ + H+ -> Cr^3+ + Fe^3+ + H2O