Which is the number of valence electrons in :
(a) sodium ion, `Na^(+)`
(b) oxide ion, `O^(2-)`

Explanation

(i) sodium ion `(Na^(+))`
No of electrons : (11-1)=10 , Electronic configuration =2,8
`therefore Na^(+)` ion has 8 valence electrons
(ii) Oxide ion `(O^(-))`
No of elctrons: (8+2)=10 , Electronic configuratino =2,8
`therefore O^(2-)` ion has 8 valence electrons.