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Compare Plutonium vs Americium

Comparing Plutonium (Pu) and Americium (Am). Atomic numbers 94 and 95 with atomic masses 244 u and 243 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
Am
Americium
#95

Periodic properties of the elements

PlutoniumAmericium
SymbolPuAm
Atomic number9495
Group00
Period77
Blockff
Element categoryActinideActinide

Physical properties

PlutoniumAmericium
Phase at STPSolidSolid
Density19.816 g/cm312 g/cm3
Atomic weight244 u243 u
Melting point912.5 K
639.35 °C
1182.83 °F		1449 K
1175.85 °C
2148.53 °F
Boiling point3505 K
3231.85 °C
5849.33 °F		2880 K
2606.85 °C
4724.33 °F

Atomic properties

PlutoniumAmericium
Electronegativity (Pauling Scale)1.281.13
Electron affinity-48.33 kJ/mol9.93 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. 578 kJ/mol
  2. 1158 kJ/mol
  3. 2132 kJ/mol
  4. 3493 kJ/mol

Electron configuration

PlutoniumAmericium
Shorthand configuration[Rn] 5f6 7s2 [Rn] 5f7 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 5f7 6s2 6p6 7s2
Electrons per shell2, 8, 18, 32, 24, 8, 22, 8, 18, 32, 25, 8, 2

History

PlutoniumAmericium
DiscoveryGlenn T. Seaborg, Arthur Wahl, Joseph W. Kennedy, Edwin McMillan (1940)Glenn T. Seaborg, R. A. James, Leon O. Morgan, A. Ghiorso (1944)
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