According to molecular orbital theorym what is the bond order for He2+?

Question

a) 0

b) 0.5

c) 1

d) 1.5

e) 2

PLease help Im soooo lost. I will give 5 pts to best asnwer

Answer 1

Since He2+ is isoelectronic to H2 (i.e. it has the same number of electrons AND the structures are the same when atomic number and mass are disregarded), it has the same bond order as H2, which is 1 (you know that H-H contains a single bond, of course?)

Specifically, the two s orbitals (one from each helium atom) combine to give a low-lying bonding orbital and a higher-energy anti-bonding orbital. Since there are only two electrons in total in the species, both can fit into the bonding orbital. Bond order is the number of bonding electrons minus the number of antibonding electrons, "all over 2", hence, (2-0)/2 = 1.