What is the electron configuration of the P3- and Mo3+ ions?

1 Answer
Nov 3, 2015

See explanation.

Explanation:

The electron configuration of ""_15P15P is:

""_15P: 1s^(2)2s^(2)2p^(6)3s^(2)3p^(3)15P:1s22s22p63s23p3

When phosphorous gains 33 electrons to form the ion P^(3-)P3 the electron configuration becomes:

""_15P^(3-): 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)15P3:1s22s22p63s23p6

The electron configuration of ""_42Mo42Mo is:

""_42Mo: 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(2)3d^(10)4p^(6)5s^(color(green)(2))4d^(color(green)(4))42Mo:1s22s22p63s23p64s23d104p65s24d4

When Molybdenum loses 33 electrons to form the ion Mo^(3+)Mo3+ the electron configuration becomes:
""_42Mo^(3+): 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(2)3d^(10)4p^(6)5s^(color(red)(0))4d^(color(red)(3))42Mo3+:1s22s22p63s23p64s23d104p65s04d3

Some people they get confused and remove the 33 electrons from 4d^(4)4d4 first, however, the electrons will be removed from 5s^(2)5s2 first and the remaining 11 electron will be removed from 4d^(4)4d4.

You should keep in mind that the 5s5s orbital gets filled before the 4d4d orbital, however, when removing electrons; the electrons will be removed from 5s5s first.