Harmony J. answered 03/18/20
20 years tutoring experience and a published author of a Kaplan book
Since Li forms a +1 ion and P forms a -3 ion they are in a 3:1 ratio
the formula of the compound is Li3P
electron configuration of Li is 1s22s1
as an Li+ ion the electron configuration is 1s2 because it loses its valence electron
electron configuration of P is 1s22s22p63s23p3
as a P3- ion its electron configuration is 1s22s22p63s23p6 because it has gained 3 valence electrons