042Transition metal · Group 6 · Period 5
Molybdenum
Molybdenum (Mo) is element 42, a transition metal in the d-block — group 6, period 5. It is a solid at room temperature with 5 electron shells (2, 8, 18, 13, 1) and an atomic mass of 95.951 u.
- Atomic mass
- 95.95 u
- Phase · STP
- solid
- Melting
- 2896 K · 2623 °C
- Boiling
- 4912 K · 4639 °C
- Electronegativity
- 2.16
- Density
- 10.28 g/cm³
Photograph — Jurii, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons, source: https://images-of-elements.com/molybdenum.php
Identity
- Atomic number
- 42
- Standard atomic weight
- 95.95 u
- Category
- Transition metal
- Group
- 6
- Period
- 5
- Block
- d-block
- Oxidation states
- +6
Physical properties
- Melting point
- 2896 K · 2623 °C
- Boiling point
- 4912 K · 4639 °C
- Density
- 10.28 g/cm³
- Molar heat capacity
- 24.06 J/(mol·K)
- Atomic radius
- 209 pm
- Electron affinity
- 72.1 kJ/mol
Atomic structure
42protons
54neutrons
42electrons
1valence e⁻
- Noble-gas notation
- [Kr] 4d5 5s1
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s1 4d5
- Electrons per shell
- 2, 8, 18, 13, 1
Periodic trends
Where Molybdenum ranks across all 118 elements.
Ionization energies
Energy to remove each successive electron (kJ/mol).
684.31
1.6k2
2.6k3
4.5k4
5.3k5
6.6k6
12.1k7
13.9k8
15.8k9
18.0k10
Successive ionization energies (kJ/mol, log scale).
Discovery
- Discovered
- 1778
- Discovered by
- Carl Wilhelm Scheele
- Named by
- —
- Appearance
- gray metallic