93
Np
Neptunium
Actinide period 7 f-block discovered: 1940
As a chemical element
Properties of the atom — they do not depend on what substance it is part of.
- Atomic number
- 93
- Atomic mass
- 237.048172 a.m.u.
- Electron configuration
- [Rn]7s2 5f4 6d1
- Electronegativity
- 1.36 on the Pauling scale
- Atomic radius
- 221 pm
- Ionization energy
- 6.266 eV
- Oxidation states
- +6, +5, +4, +3
As a simple substance
Properties of the substance these atoms form under ordinary conditions.
- State at 25 °C
- Solid
- Melting point
- 917 K (643,85 °C)
- Boiling point
- 4175 K (3 901,85 °C)
- Density
- 20.25 g/cm³