Element 24
Chromium (Cr)
Chromium (Cr) is element 24 of the periodic table, a transition metal in period 4, group 6 (d-block) with an atomic mass of 51.996 and is a solid at standard conditions.
At a glance
- Atomic number
- 24
- Symbol
- Cr
- Atomic mass
- 51.996 u
- Category
- Transition metals
- Period
- 4
- Group
- 6
- Block
- d-block
- Phase at STP
- solid
Electron structure
- Electron configuration
- 1s2 2s2 2p6 3s2 3p6 3d5 4s1
- Shorthand configuration
- [Ar] 3d5 4s1
- Electrons per shell
- 2, 8, 13, 1
- Oxidation states
- -4, -2, -1, +1, +2, +3, +4, +5, +6
Physical properties
- Melting point
- 2,180 K (1,906.85 °C)
- Boiling point
- 2,944 K (2,670.85 °C)
- Density
- 7.15 g/cm³
- Phase
- solid
Atomic properties
- Electronegativity (Pauling)
- 1.66
- Atomic radius
- 166 pm
- Covalent radius
- 139 pm
- First ionization energy
- 653 kJ/mol
- Electron affinity
- 64 kJ/mol
Notable isotopes
| Isotope | Mass | Abundance | Stability |
|---|---|---|---|
| Cr-52 | 51.94051 | 83.79% | Stable |
Common uses
- Stainless steel
- Chrome plating
- Dyes
- Wood preservation
Discovery
- Year
- 1797
- Discovered by
- Louis Nicolas Vauquelin
- Country
- France
Frequently asked questions
- Is chromium a metal?
- Yes. Chromium is a metal, classified as a transition metal on the periodic table.
- How many protons does chromium have?
- Chromium has 24 protons. Its atomic number is 24, which is also the number of electrons in a neutral atom of chromium.
- What group and period is chromium in?
- Chromium is in group 6 and period 4 of the periodic table, in the d-block.
- What is the atomic mass of chromium?
- The atomic mass of chromium is 51.996 u (unified atomic mass units).
Keep exploring
Chromium's row is on the printable element property sheet, and its tile is on the periodic table wall chart - the same numbers as above, laid out for A4 or A3 paper.