2451.996CrChromium
Chromium (Cr) — element 24transition metal · group 6, period 4
Chromium is a chemical element with the symbol Cr and atomic number 24. It is a transition metal in group 6, period 4 of the periodic table (the d-block), with a standard atomic mass of 51.996 u. At room temperature (25 °C) chromium is a solid.
💡 Known for: Gives stainless steel its corrosion resistance and chrome plating its mirror shine.
# Chromium properties
| Symbol | Cr |
|---|---|
| Atomic number | 24 |
| Atomic mass | 51.996 u |
| Category | transition metal |
| Group | 6 |
| Period | 4 |
| Block | d-block |
| Electron configuration | [Ar] 3d⁵ 4s¹ |
| Full configuration | 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s¹ |
| Electrons per shell | 2, 8, 13, 1 |
| Protons / electrons | 24 / 24 |
| State at 25 °C | solid |
| Melting point | 2180 K (1906.8 °C, 3464.3 °F) |
| Boiling point | 2944 K (2670.8 °C, 4839.5 °F) |
| Density | 7.15 g/cm³ |
| Electronegativity (Pauling) | 1.66 |
| First ionization energy | 6.767 eV |
| Atomic radius | 166 pm |
| Discovered | 1797 |
# Electron configuration of chromium
The electron configuration of chromium is [Ar] 3d⁵ 4s¹, written out in full as 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s¹. Its 24 electrons fill 4 shells as 2, 8, 13, 1, so the outermost shell holds 1 electron.
# Related elements
VVanadiumprevious elementMnManganesenext elementMoMolybdenumgroup 6WTungstengroup 6SgSeaborgiumgroup 6ScScandiumtransition metalTiTitaniumtransition metalFeIrontransition metalCoCobalttransition metalNiNickeltransition metalCuCoppertransition metalZnZinctransition metalYYttriumtransition metal
# Chromium FAQ
What is the atomic number of chromium?
The atomic number of chromium is 24: every chromium atom has 24 protons in its nucleus. Its symbol is Cr.
What is the atomic mass of chromium?
The standard atomic mass of chromium is 51.996 u.
What is the electron configuration of chromium?
Chromium's electron configuration is [Ar] 3d⁵ 4s¹ (1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s¹), with 2, 8, 13, 1 electrons per shell.
Is chromium a metal?
Yes. Chromium is a transition metal, one of the metals.
What is the melting point of chromium?
Chromium melts at 2180 K (1906.8 °C, 3464.3 °F) and boils at 2944 K (2670.8 °C, 4839.5 °F).
What is chromium used for / known for?
Gives stainless steel its corrosion resistance and chrome plating its mirror shine.