93 · Np
Neptunium
Produced at Berkeley in 1940 by McMillan and Abelson.
Identity
- Atomic number
- 93
- Symbol
- Np
- Canonical name
- Neptunium
- Category
- actinide
- Group
- unassigned
- Period
- 7
- Block
- f
Series set apart from the main table. Whether group 3 is lanthanum or lutetium (actinium or lawrencium) is still discussed, so the group is left empty.
Properties
These quantities come from the Periodic Table JSON compilation. They have not yet been checked, one by one, against CIAAW atomic weights or NIST measurements. A value marked estimated is not a measurement.
- Atomic mass
- [237] No standard atomic weight. The number shown is the conventional mass number used in tables, not a measured mass in u.
- Electron configuration
- [Rn] 5f4 6d1 7s2
- Electrons per shell
- 2, 8, 18, 32, 22, 9, 2
- Standard state
- solid
- Density
- 20.45 g/cm³
- Melting point
- 912 K
- Boiling point
- 4,447 K
- Electronegativity
- 1.36 Pauling
- First ionization energy
- 604.5 kJ/mol
- Electron affinity
- 45.85 kJ/mol
Notable isotopes
This summary is not an inventory of every isotope.
Conventional mass number: 237
History
Neptunium
Synthesis · confirmed · 1940
McMillan and Abelson identify neptunium after irradiating uranium.
- Target
- 238U
- Projectile
- neutrons
- Isotope produced
- 239Np
- Instrument
- cyclotron, then neutron capture
Etymology
- Theme
- celestial body
- Language
- latin
- Root
- Neptunus
- Meaning
- Neptune
Scientists
Places and institutions
- Berkeley — historical setting : United States — present country : United States
See also
Sources
- IUPAC, Periodic Table of the Elements
- Bowserinator, Periodic Table JSON. Compilation secondaire d’où viennent les grandeurs physiques importées (masse, densité, températures, énergies). Elles ne sont pas revérifiées une à une auprès du NIST ou de la CIAAW.
- IUPAC, décisions sur la priorité et les noms des éléments transfermiens (1997–2016)