Giải Ta có:\(\eqalign{
& Cl\left( {Z = 17} \right):\,\,1{s^2}2{s^2}2{p^6}3{s^2}3{p^5}\cr& S\left( {Z = 16} \right):\,\,1{s^2}2{s^2}2{p^6}3{s^2}3{p^4} \cr
& O\left( {Z = 8} \right):\,\,1{s^2}2{s^2}2{p^4}\cr&F\left( {Z = 9} \right):\,\,1{s^2}2{s^2}2{p^5} \cr} \)Vậy: A – d B – c C – b D – a
