Transition metals
Chromium
A lustrous metal that gives stainless steel its shine.
Atomic #24Mass51.996Blockd-blockPeriod4Group6
Cr24 · 51.996
3D Atom Explorer
Inside the Chromium atom
Switch between Bohr and Quantum Cloud modes to compare a simple teaching model with a more realistic probability-based view, and follow the guided tour to explore the Chromium atom step by step.
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Electron configuration
[Ar] 3d5 4s1
A neutral Chromium atom has 24 electrons (equal to its proton count). Choosing a different isotope above changes only the neutron count.
Shell distribution
Shell 12 e⁻Shell 28 e⁻Shell 313 e⁻Shell 41 e⁻
Electrons fill inner shells before outer ones; the outermost (valence) shell drives the element's chemistry.
Properties
Physical & atomic properties
- State (room temp)
- Solid
- Melting point
- 2180 K (1907 °C)
- Boiling point
- 2944 K (2671 °C)
- Density
- 7.15 g/cm³
- Electronegativity
- 1.66 Pauling
- Atomic radius
- 140 pm
- 1st ionization energy
- 653 kJ/mol
- Category
- Transition metals
History
Discovery & naming
- Discovered
- 1797
- Discovered by
- Louis-Nicolas Vauquelin
- Origin of name
- Greek 'chroma', meaning colour.
Notable uses
Stainless steel, chrome plating, and pigments.
Cosmic origin
Where Chromium comes from
Supernovae
Made by explosive silicon burning, with large contributions from thermonuclear (Type Ia) supernovae.
Simplified origin map — many elements form through more than one astrophysical pathway.
Summary
- Atomic number
- 24
- Atomic mass
- 51.996
- Category
- Transition metals
- Group · Period
- 6 · 4
- Block
- d-block
- Shells
- 2 · 8 · 13 · 1