a) Na: $1s^{2}$$2s^{2}$$2p^{6}$$3s^{1}$
Al: $1s^{2}$$2s^{2}$$2p^{6}$$3s^{2}$$3p^{1}$
S : $1s^{2}$$2s^{2}$$2p^{6}$$3s^{2}$$3p^{4}$
Cl: $1s^{2}$$2s^{2}$$2p^{6}$$3s^{2}$$3p^{5}$
Ni: $1s^{2}$$2s^{2}$$2p^{6}$$3s^{2}$$3p^{6}$$3d^{8}$$4s^{2}$
Zn: $1s^{2}$$2s^{2}$ $2p^{6}$$3s^{2}$$3p^{6}$$3d^{10}$$4s^{2}$
b) $Na^{+}$: $1s^{2}$$2s^{2}$$2p^{6}$
$Al^{3-}$: $1s^{2}$$2s^{2}$$2p^{6}$
$S^{2-}$: $1s^{2}$$2s^{2}$$2p^{6}$$3s^{2}$$3p^{6}$
$Cl^{-}$: $1s^{2}$$2s^{2}$$2p^{6}$$3s^{2}$$3p^{6}$
c) số e ion dương: giảm
số e ion âm: tăng
