Question

Between $\mathrm{Ca}(\mathrm{Z}=20)$ and $\mathrm{Zn}(\mathrm{Z}=30)$:

a. Which is more metallic?

b. Whose oxide is more basic? Explain your choice.

Answer 1

a)

1. The metallic character decreases from left to right in a period. Calcium (Ca) is present in the $2^{\mathrm{nd}}$group and Zinc (Zn) is located in the ${12}^{th}$group of the periodic table.
2. Both Calcium and Zinc have two electrons in their outermost shell. But the atomic radius of Zinc is less than that of Calcium. So, Calcium can lose electrons easily compared to Zinc.
3. Metals have a characteristic property of forming electropositive ions.
4. Thus, Calcium is more metallic than Zinc.

(b)

1. The oxide of Calcium is $\mathrm{CaO}$ and of Zinc is $\mathrm{ZnO}$.
2. In a period as we move from left to the right basic character and electrovalency decrease and in a group basic character increases from top to bottom.
3. Also, $\mathrm{ZnO}$ is amphoteric in nature i.e. it is both acidic and basic.
4. Hence, $\mathrm{CaO}$ is more basic than $\mathrm{ZnO}$ .