Three elements X, Y and Z are in the 3rd period of the periodic table. The oxides of X, Y and Z, respectively, are basic, amphoteric and acidic. The correct order of the atomic numbers of X, Y and Z is:

Oxide of x $\to$ Basic

$\Rightarrow \mathrm{IA}\mathrm{or}\mathrm{IIA}$

Oxide of $\mathrm{y}\to$ amphoteric$\Rightarrow \mathrm{IIIA}$

Oxide of $\mathrm{z}\to \mathrm{acidic}$       

$\Rightarrow$IVA or VA or VIA or VIIA

Atomic number order is x < y < z   (or)

As we move across the period, acidic nature of oxides increases.

          $\therefore$ x < y < z