S-2 has complete;y filled with K,L and M shells.Find its atomic number..
As S-2 has completely filled K, L, M shell, therefore the total number of electron present in S-2 is equal to 18.
As the symbol suggest, sulphur has gained 2 electron. Therefore number of electron in sulphur atom is 16.
As the atomic number is the number of proton in a neutral atom, therefore number number of protons = 16 and hence its atomic number is 16.