Element 42
Molybdenum (Mo)
Molybdenum (Mo) is element 42 of the periodic table, a transition metal in period 5, group 6 (d-block) with an atomic mass of 95.95 and is a solid at standard conditions.
At a glance
- Atomic number
- 42
- Symbol
- Mo
- Atomic mass
- 95.95 u
- Category
- Transition metals
- Period
- 5
- Group
- 6
- Block
- d-block
- Phase at STP
- solid
Electron structure
- Electron configuration
- 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d5 5s1
- Shorthand configuration
- [Kr] 4d5 5s1
- Electrons per shell
- 2, 8, 18, 13, 1
- Oxidation states
- -4, -2, -1, +1, +2, +3, +4, +5, +6
Physical properties
- Melting point
- 2,896 K (2,622.85 °C)
- Boiling point
- 4,912 K (4,638.85 °C)
- Density
- 10.22 g/cm³
- Phase
- solid
Atomic properties
- Electronegativity (Pauling)
- 2.16
- Atomic radius
- 190 pm
- Covalent radius
- 154 pm
- First ionization energy
- 684 kJ/mol
- Electron affinity
- 72 kJ/mol
Notable isotopes
| Isotope | Mass | Abundance | Stability |
|---|---|---|---|
| Mo-98 | 97.90541 | 24.13% | Stable |
Common uses
- Steel alloys
- Catalysts
- Lubricants
- Electronics
Discovery
- Year
- 1781
- Discovered by
- Carl Wilhelm Scheele
- Country
- Sweden
Frequently asked questions
- Is molybdenum a metal?
- Yes. Molybdenum is a metal, classified as a transition metal on the periodic table.
- How many protons does molybdenum have?
- Molybdenum has 42 protons. Its atomic number is 42, which is also the number of electrons in a neutral atom of molybdenum.
- What group and period is molybdenum in?
- Molybdenum is in group 6 and period 5 of the periodic table, in the d-block.
- What is the atomic mass of molybdenum?
- The atomic mass of molybdenum is 95.95 u (unified atomic mass units).
Keep exploring
Molybdenum'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.