Three elements $X$,$Y$,and $Z$ having atomic numbers $11$,$7$,and $6$ respectively react with oxygen to form their oxides.
$(a)$ Arrange these oxides in increasing order of their basic nature.
$(b)$ Give reason for your answer.

(A) The electronic configurations are:
${ }_{11}X = 2, 8, 1$ (Metal)
${ }_{7}Y = 2, 5$ (Non-metal)
${ }_{6}Z = 2, 4$ (Non-metal)
$(a)$ The increasing order of basic nature is: $Y_2O_5 < ZO_2 < X_2O$.
$(b)$ $X$ (Sodium) is a metal,so its oxide $(Na_2O)$ is strongly basic. $Y$ (Nitrogen) and $Z$ (Carbon) are non-metals,so their oxides ($N_2O_5$ and $CO_2$) are acidic. Among non-metals,the acidity decreases as we move from right to left in a period. Therefore,the basic character increases from $Y$ to $Z$ to $X$.