The atomic number of an element 'X' is 11.

(i) Write the electronic configurations of X and find its valency.

(ii) Write the formula and nature of its oxide.

(i) Electronic Configuration and Valency of X:

• Since the atomic number of element $X$ is $11$, it is Sodium ($\text{Na}$).
• Its electronic configuration is $2, 8, 1$.
• Since it has $1$ valence electron in its outermost shell, it loses this electron to achieve a stable octet configuration. Therefore, the valency of $X$ is $1$.

(ii) Formula and Nature of its Oxide:

• Formula: The valency of $X$ (Sodium) is $1$ and that of Oxygen is $2$. By crossing over their valencies, the chemical formula of its oxide is $\text{Na}_2\text{O}$ (Sodium oxide).
• Nature: The oxide is basic in nature. When dissolved in water, it forms a strong alkali, sodium hydroxide ($\text{NaOH}$), which turns red litmus paper blue:

$$\text{Na}_2\text{O(s)} + \text{H}_2\text{O(l)} \rightarrow 2\text{NaOH(aq)}$$