Periodic table / Transition metals
42Molybdenum
Molybdenum is a transition metal in group 6, period 5. At 25 °C it is a solid.
- Symbol
- Mo
- Atomic number
- 42 protons in the nucleus
- Standard atomic weight
- 95.95 ± 0.01Some geological samples have an unusual isotope mix, so their atomic weight can fall outside this range.
- Electron configuration
- [Kr] 4d5 5s1
- Electrons in each shell
- 2, 8, 18, 13, 1
- Group, period, block
- 6, 5, d
- Family
- Transition metals
- State at 25 °C
- solid
- Electronegativity
- 2.16 (Pauling scale)
- First ionisation energy
- 684.3 kJ/mol (7.09243 eV)
Where these numbers come from
Atomic weight: IUPAC CIAAW, abridged standard atomic weights 2024. Electron configuration and ionisation energy: NIST Atomic Spectra Database. Family, state and electronegativity: PubChem. See Sources. Melting points, boiling points and densities are left out for now: published values differ between sources, and we will add them once each has been checked.