Periodic table

 

 

Atomic number:93

Group numbers:3

Period:7

Electronic configuration:[Rn] 5f⁴ 6d¹ 7s²

Formal oxidation number:+3 +4 +5 +6

Electronegativities:1.3

Atomic radius / pm:130

Relative atomic mass:[237]

 

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.

PHYSICAL PROPERTIES

Density / g dm^-3:20250 (293 K)

Molar volume / cm³mol^-1:11.70 (293 K)

Electrical resistivity / μΩcm:122 (20 °C)

THERMAL PROPERTIES

Thermal conductivity / W m^-1K^-1:6.3

Melting point / °C:644

Boiling point / °C:3902

Heat of fusion / kJ mol^-1:9.46

Heat of vaporization / kJ mol^-1:336.6

Heat of atomization / kJ mol^-1:457

IONIZATION ENERGIES

First ionization energy / kJ mol^-1:604.55

Second ionization energy / kJ mol^-1:-

Third ionization energy / kJ mol^-1:-

ABUNDANCE OF ELEMENTS

in the atmosphere / ppm:-

in the Earth's crust / ppm:-

in the oceans / ppm:-

CRYSTALLOGRAPHIC DATA

ISOTOPES

REDUCTION POTENTIALS

 

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Citing this page:

Generalic, Eni. "Neptunium." EniG. Periodic Table of the Elements. 3 Jan. 2012. KTF-Split. {Date of access}. <http://www.periodni.com/np.html>.