Question

Sort these species into isoelectronic groups. It doesn't matter which group goes in which box, so long as the correct species are grouped.

Ne Mg2+ S2- Ti4+ K+ He Li+ Be2+ N3-

Answer 1

I believe you have them grouped right except for N^3- but you don't delineate between the groups very well. I think you should put them in "boxes" so to speak, something like this just to separate them.

Ne Mg2+
S2- Ti4+ K+
He Li+ Be2+

I think N3- should go with Ne and Mg^2+. I don't know how you did this but you can count the electrons since that is what isoelectronic means.
Ne has 10, Mg^2+ is 12-2=10, and N^3- is 7+3 = 10

Answer 2

Sort these species into isoelectronic groups. It doesn\'t matter which group goes in which box, so long as the correct species are grouped.

Answer 3

2 Electrons: Ba2+ , Li+ , He
10 Electrons: N3- , Ne, Mg2+
36 Electrons: Rb+ , Y3+ , Se2-