Neptunium - ASCII Periodic Table of the Elements

ASCII PERIODIC TABLE OF THE ELEMENTS

  Np

Relative atomic mass: [237]

English: Neptunium
French: Neptunium
Croatian: Neptunij
German: Neptunium
Italian: Nettunio
Spanish: Neptunio

Atomic number: 93
Group numbers: 3
Period: 7
Standard state (20 °C): solid

Discovery: 1940 Edwin Mattison McMillan, Philip Hauge Abelson (US)

Neptunium was discovered by Edwin Mattison McMillan and Philip Hauge Abelson (US) in 1940. Named after the planet 'Neptune'. It is a rare, silvery radioactive, radiotoxic metal that resists alkalis, reacts with oxygen, acid and steam. Neptunium was produced by bombarding uranium with slow neutrons.

Electronic configuration: [Rn] 5f⁴ 6d¹ 7s²
Formal oxidation number: +3 +4 +5 +6
Atomic radius: 130 pm

Electronegativities: 1.3
Thermal conductivity: 6.3 W/(m K)
Electrical resistivity (20 °C): 122 μΩcm

Melting point: 644 °C
Boiling point: 3902 °C

Heat of fusion: 9.46 kJ/mol
Heat of vaporization: 336.6 kJ/mol
Heat of atomization: 457 kJ/mol