Question

Write the atomic number and valency of the following elements:
(i) Oxygen
(ii) Potassium

Hint:

Oxygen typically has a valency of 2 because it needs 2 electrons to complete its valence shell, while potassium has a valency of 1 because it loses 1 electron to achieve a stable configuration.

Answer 1

(i) Oxygen:
- Atomic Number: 8
- Valency: 2 (Oxygen can form two bonds, as in water \( \text{H}_2\text{O} \), where oxygen bonds with two hydrogen atoms).

(ii) Potassium:
- Atomic Number: 19
- Valency: 1 (Potassium has a valency of 1, as it loses one electron to form \( \text{K}^+ \) ion, as seen in potassium chloride \( \text{KCl} \)).

Conclusion:
1. The atomic number of oxygen is 8, and its valency is 2.
2. The atomic number of potassium is 19, and its valency is 1.