In which of the following species both cation and Anion have same number of electrons

Which of the following species have the same number of electrons in its outermost as well as penultimate shell ?

Which of the following species has the same number of electrons in the outermost and penultimate shells?

In which of the following pairs, both species have not nearly the same size ?

Which of the following are isoelectronic species i.e., having the same number of electrons ? Na ^(+) , K ^(+), Mg ^(2+) , Ca ^(2+), S ^(2-) Ar ,