42Mo95.951
Transition Metald-block
Molybdenum
Element 42 on the periodic table, symbol Mo, group 6, period 5.
Molybdenum is a chemical element with symbol Mo and atomic number 42. The name is from Neo-Latin molybdaenum, from Ancient Greek Μόλυβδος molybdos, meaning lead, since its ores were confused with lead ores. Molybdenum minerals have been known throughout history, but the element was discovered (in the sense of differentiating it as a new entity from the mineral salts of other metals) in 1778 by Carl Wilhelm Scheele.
Appearance: gray metallic
Properties
- Atomic Number
- 42
- Atomic Mass
- 95.9510 u
- Group
- 6
- Period
- 5
- Block
- d-block
- Category
- Transition Metal
- State at 25 °C
- Solid
- Melting Point
- 2,896 K · 2,622.9 °C
- Boiling Point
- 4,912 K · 4,638.9 °C
- Density
- 10.28 g/cm³
- Atomic Radius
- 145 pm
- Electronegativity
- 2.16
- Oxidation States
- +4, +6
- Abundance in Crust
- 1.2 mg/kg
- Discovered
- 1781
- Discovered By
- Carl Wilhelm Scheele
Electron Configuration
[Kr] 4d5 5s1
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s1 4d5
Ionisation Energies (kJ/mol)
- 1. 684.3
- 2. 1,560
- 3. 2,618
- 4. 4,480
- 5. 5,257
- 6. 6,640.8
- 7. 12,125
- 8. 13,860
Elements near Molybdenum
Elements in the same group share the number of outer electrons and behave in similar ways. Elements in the same period share a shell, so they change steadily from left to right.