Np
Neptunium · element 93
Actinide · Solid at room temperature
Neptunium is a chemical element with symbol Np and atomic number 93. A radioactive actinide metal, neptunium is the first transuranic element. Its position in the periodic table just after uranium, named after the planet Uranus, led to it being named after Neptune, the next planet beyond Uranus.
Key facts
Atomic mass
237 u
how heavy one atom is
Phase (room temp.)
Solid
Density
20.45 g/cm³
how tightly packed it is
Melting point
912 K (639 °C)
when solid turns to liquid
Boiling point
4447 K (4174 °C)
when liquid turns to gas
Period
7
its row in the periodic table
Group
3
its column in the periodic table
Block
F-block
the neighbourhood it lives in
Electronegativity
1.36
how strongly it pulls electrons
Electron configuration
[Rn] 5f4 6d1 7s2
where its electrons live
Shells
2 · 8 · 18 · 32 · 22 · 9 · 2
electrons in each layer, inside to out
Discovered by
Edwin McMillan
who found it
Appearance
silvery metallic
what it looks like
Source: Wikipedia