State three reasons for counting sulphur amongst non-metals.

The electronic configurations of three elements X, Y and Z are as follows:

X - $2, 8$

Y - $2, 8, 7$

Z - $2, 8, 2$

Which of the following is correct?

Which of the following are not ionic compounds?

(i)$\mathrm{KCl}$ (ii)$\mathrm{HCl}$ (iii)${\mathrm{CCl}}_4$ (iv)$\mathrm{NaCl}$