Discovered By: Edwin McMillan, Philip Hauge Abelson
Discovery year: 1940

The following table showing some properties of Neptunium(Np):

Table Example
Atomic number 93
Group n/a
Period 7
Block f
Electrons 93
Protons 93
Neutrons 144
Atomic weight (237)
Oxidation states +3, +4, +5, +6
Ionic charge Np^5+


Table Example
Electrons per shell K2 L8 M18 N32 O22 P9 Q2
Covalent radius 190 pm
Electron configuration 1s^2 2s^2 2p^6 3s^2 3p66 4s^2 3d^10 4p^6 5s^2 4d^10 5p^6 6s^2 4f^14 5d^10 6p66 7s^2 5f^4 6d^1
Boiling point 4000°C
Melting point 644°C
Phase Solid
Fusion heat 10 kJ.mol^-1
Vaporization heat 335 kJ.mol^-1
Color Silver
Density 20450 kg.m^-3


Table Example
Electrical type Conductor
Resistivity 1.2*10^-6 Ohm.m
Electronegativity 1.36
valence 6
First ionization energy 604.5 kJ.mol^-1
Radioactive Yes
Half life 6.766*10^13 s
Lifetime 9.761*10^13 s
Neutron cross section 180 barn
Decay mode Alpha emission (α-decay)