4295.95MoMolybdenum
Molybdenum (Mo) — element 42transition metal · group 6, period 5
Molybdenum is a chemical element with the symbol Mo and atomic number 42. It is a transition metal in group 6, period 5 of the periodic table (the d-block), with a standard atomic mass of 95.95 u. At room temperature (25 °C) molybdenum is a solid.
💡 Known for: Keeps steel strong at high temperatures and is essential for key enzymes in plants and animals.
# Molybdenum properties
| Symbol | Mo |
|---|---|
| Atomic number | 42 |
| Atomic mass | 95.95 u |
| Category | transition metal |
| Group | 6 |
| Period | 5 |
| Block | d-block |
| Electron configuration | [Kr] 4d⁵ 5s¹ |
| Full configuration | 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d⁵ 5s¹ |
| Electrons per shell | 2, 8, 18, 13, 1 |
| Protons / electrons | 42 / 42 |
| State at 25 °C | solid |
| Melting point | 2896 K (2622.8 °C, 4753.1 °F) |
| Boiling point | 4912 K (4638.9 °C, 8381.9 °F) |
| Density | 10.22 g/cm³ |
| Electronegativity (Pauling) | 2.16 |
| First ionization energy | 7.092 eV |
| Atomic radius | 190 pm |
| Discovered | 1781 |
# Electron configuration of molybdenum
The electron configuration of molybdenum is [Kr] 4d⁵ 5s¹, written out in full as 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d⁵ 5s¹. Its 42 electrons fill 5 shells as 2, 8, 18, 13, 1, so the outermost shell holds 1 electron.
# Related elements
NbNiobiumprevious elementTcTechnetiumnext elementCrChromiumgroup 6WTungstengroup 6SgSeaborgiumgroup 6ScScandiumtransition metalTiTitaniumtransition metalVVanadiumtransition metalMnManganesetransition metalFeIrontransition metalCoCobalttransition metalNiNickeltransition metalCuCoppertransition metal
# Molybdenum FAQ
What is the atomic number of molybdenum?
The atomic number of molybdenum is 42: every molybdenum atom has 42 protons in its nucleus. Its symbol is Mo.
What is the atomic mass of molybdenum?
The standard atomic mass of molybdenum is 95.95 u.
What is the electron configuration of molybdenum?
Molybdenum's electron configuration is [Kr] 4d⁵ 5s¹ (1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d⁵ 5s¹), with 2, 8, 18, 13, 1 electrons per shell.
Is molybdenum a metal?
Yes. Molybdenum is a transition metal, one of the metals.
What is the melting point of molybdenum?
Molybdenum melts at 2896 K (2622.8 °C, 4753.1 °F) and boils at 4912 K (4638.9 °C, 8381.9 °F).
What is molybdenum used for / known for?
Keeps steel strong at high temperatures and is essential for key enzymes in plants and animals.