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-
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
Sort these species into isoelectronic groups. It doesn\'t matter which group goes in which box, so long as the correct species are grouped.
2 Electrons: Ba2+ , Li+ , He
10 Electrons: N3- , Ne, Mg2+
36 Electrons: Rb+ , Y3+ , Se2-
To determine the isoelectronic groups, we need to compare the number of electrons for each species. Isoelectronic species have the same number of electrons.
Let's write down the electron configuration for each species:
Ne: 1s^2 2s^2 2p^6
Mg2+: 1s^2 2s^2 2p^6
S2-: 1s^2 2s^2 2p^6 3s^2 3p^6
Ti4+: 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^0
K+: 1s^2 2s^2 2p^6 3s^2 3p^6
He: 1s^2
Li+: 1s^2 2s^0
Be2+: 1s^2 2s^0
N3-: 1s^2 2s^2 2p^6
Now, let's group them based on the number of electrons they have:
Group 1: Ne, Mg2+, S2-
Group 2: Ti4+, K+, He
Group 3: Li+, Be2+, N3-
In group 1, Ne, Mg2+, and S2- have the same electron configuration with 10 electrons.
In group 2, Ti4+, K+, and He have the same electron configuration with 2 electrons.
In group 3, Li+, Be2+, and N3- have the same electron configuration with 8 electrons.
Note that the number of protons and neutrons in the nucleus may be different for each species, but the focus here is on the number of electrons, which determines the chemical behavior and properties of an atom or ion.