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Compare Plutonium vs Neptunium

Comparing Plutonium (Pu) and Neptunium (Np). Atomic numbers 94 and 93 with atomic masses 244 u and 237 u, classified as actinide and actinide. Below: a side-by-side comparison of their physical, atomic, electron-configuration and historical properties, including density, melting and boiling points, ionization energies, oxidation states and discovery history.

vs
Pu
Plutonium
#94
Np
Neptunium
#93

Periodic properties of the elements

PlutoniumNeptunium
SymbolPuNp
Atomic number9493
Group00
Period77
Blockff
Element categoryActinideActinide

Physical properties

PlutoniumNeptunium
Phase at STPSolidSolid
Density19.816 g/cm320.45 g/cm3
Atomic weight244 u237 u
Melting point912.5 K
639.35 °C
1182.83 °F		912 K
638.85 °C
1181.93 °F
Boiling point3505 K
3231.85 °C
5849.33 °F		4447 K
4173.85 °C
7544.93 °F

Atomic properties

PlutoniumNeptunium
Electronegativity (Pauling Scale)1.281.36
Electron affinity-48.33 kJ/mol45.85 kJ/mol
Oxidation states+2, +3, +4, +5, +6, +7, +8
(an amphoteric oxide)		+2, +3, +4, +5, +6, +7
(an amphoteric oxide)
Ionization energies
  1. 584.7 kJ/mol
  2. 1128 kJ/mol
  3. 2084 kJ/mol
  4. 3338 kJ/mol
  1. 604.5 kJ/mol
  2. 1128 kJ/mol
  3. 1997 kJ/mol
  4. 3242 kJ/mol

Electron configuration

PlutoniumNeptunium
Shorthand configuration[Rn] 5f6 7s2 [Rn] 5f4 6d1 7s2
Full configuration1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f6 6s2 6p6 7s2 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f4 6s2 6p6 6d1 7s2
Electrons per shell2, 8, 18, 32, 24, 8, 22, 8, 18, 32, 22, 9, 2

History

PlutoniumNeptunium
DiscoveryGlenn T. Seaborg, Arthur Wahl, Joseph W. Kennedy, Edwin McMillan (1940)Edwin McMillan, Philip H. Abelson (1940)
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