JEE Chemistry 2023 Question with Solution

Given: The order of metallic character among $\text{K}$, $\text{Be}$, and $\text{Ca}$ is to be determined.

Find: The correct decreasing order of metallic character.

Metallic character increases as we move down a group and decreases as we move across a period.

• In a group, metallic character increases because atomic size increases and the attraction between valence electrons and the nucleus becomes weaker.
• In a period, metallic character decreases because effective nuclear charge increases and loss of electrons becomes more difficult.

Applying these trends:

• $\text{K}$ is more metallic than $\text{Ca}$.
• $\text{Ca}$ is more metallic than $\text{Be}$.

Therefore, the correct order of metallic character is

$$\text{K} > \text{Ca} > \text{Be}$$

So, the correct option is C.