Elements X, Y, Z have atomic numbers 6, 9 and 12 respectively. Which one :

(i) forms anion – negative ion;

(ii) forms cation – positive ion;

(iii) has 4 electrons in the outermost orbit.

X[6] = Electronic configuration [2,4]
Y[9] = Electronic configuration [2,7]
Z[12] = Electronic configuration [2,8,2]

(i) Y gains one electron to attain a stable octet, hence becomes negatively charged anion.

(ii) Z loses two electrons to attain a stable octet hence becomes positively charged cation.

(iii) X has 4 electrons in the outer most shell.