Respuesta :

This is the electron configuration of neptunium:
Rn 5f4 6d1 7s2
or, if you want to complicate:
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f4 6d1
Since there are 93 electrons, they make up 5f4 altogether.