Np
Neptunium
Element 93 · Actinide
Neptunium (Np)
Neptunium is a radioactive metal and the first transuranium element ever made.
- Actinide
- Period 7
- f-block series
- f-block
- solid at room temperature
- ☢ Radioactive
Key properties
- Atomic mass
- [237]
- u
- Electron configuration
- [Rn] 5f4 6d1 7s2
- Melting point
- 643.9 °C
- 917 K
- Boiling point
- 3,901.9 °C
- 4,175 K
- Density
- 20.25 g/cm³
- Electronegativity
- 1.36
- Pauling
- Atomic radius
- 221 pm
- van der Waals
- 1st ionisation energy
- 6.266 eV
Compare with every element:Electronegativity chartAtomic radius chartIonisation energy chartDensity chart of the elementsMelting point chartElectron configuration chart
Did you know?
Notable facts about neptunium
- 01
It was made by bombarding uranium with neutrons at Berkeley.
- 02
Traces of neptunium occur naturally in uranium ores.
- 03
Neptunium-237 is used to make plutonium-238 for space batteries.
Applications
What is neptunium used for?
- Production of Pu-238
- Neutron detectors
History
Discovery & name origin
Discovered by
Year
Where
United States
Name origin
From Neptune, the planet beyond Uranus.
Atomic structure
Atomic properties
Atomic structure
Atomic properties
- Atomic number
- 93
- Atomic mass
- [237] u
- Group
- Actinides (3)
- Period
- 7
- Block
- f-block
- Electron configuration
- [Rn] 5f4 6d1 7s2
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f4 6d1
- Electrons per shell
- 2, 8, 18, 32, 22, 9, 2
- Electronegativity (Pauling)
- 1.36
- Electron affinity
- —
- Atomic radius (van der Waals)
- 221 pm
- Stable isotopes
- None — all isotopes are radioactive
Oxidation states
Highlighted: common oxidation states (+6, +5, +4, +3).
Physical
Physical properties & colour
Physical
Physical properties & colour
- State at 20 °C
- Solid
- Melting point
- 917 K · 643.9 °C · 1,190.9 °F
- Boiling point
- 4,175 K · 3,901.9 °C · 7,055.3 °F
- Density
- 20.25 g/cm³
- Molar heat capacity
- 29.46 J/(mol·K)
- Appearance
- Silvery metallic
- CPK model colour
- Copied
The CPK colour is the convention used for this element’s atoms in molecular models.
FAQ
Neptunium questions
What is Np on the periodic table?
Np is the symbol for neptunium, element 93 on the periodic table. It sits in period 7, in the f-block, in the actinide category, and has an atomic mass of [237].
What is the atomic number of neptunium?
Neptunium has atomic number 93, so every neptunium atom has 93 protons in its nucleus. Its symbol is Np and its atomic mass is [237].
Who discovered neptunium?
Neptunium was discovered by Edwin McMillan and Philip Abelson in 1940 (United States). The name comes from from Neptune, the planet beyond Uranus.
What is neptunium used for?
Neptunium is used for: production of Pu-238; neutron detectors.
Is neptunium a metal?
Yes. Neptunium is a actinide, one of the metallic elements.
What is the electron configuration of neptunium?
The electron configuration of neptunium is [Rn] 5f4 6d1 7s2. Its 93 electrons are arranged in shells as 2, 8, 18, 32, 22, 9, 2.