State true or false
Oxygen is a gas but sulphur a solid.

Explanation

To determine whether the statement "Oxygen is a gas but sulphur is a solid" is true or false, we can analyze the properties of both elements.

### Step-by-Step Solution:

1. **Identify the States of Matter**:
- Oxygen (O) is known to exist as a diatomic molecule (O₂) and is a gas at room temperature.
- Sulphur (S) exists in several allotropes, with the most common being the octatomic form (S₈), which is a solid at room temperature.

2. **Group Characteristics**:
- Both oxygen and sulphur belong to Group 16 of the periodic table, also known as the chalcogens. As we move down the group from oxygen to sulphur, the size of the atoms increases.

3. **Atomic Size and Bonding**:
- Oxygen has a smaller atomic size compared to sulphur. This smaller size allows oxygen to form strong p-pi bonds, leading to the formation of the diatomic O₂ molecule.
- Sulphur, being larger, tends to form S-S single bonds and exists as S₈ molecules, which have a puckered ring structure.

4. **Intermolecular Forces**:
- The intermolecular forces in oxygen are weak van der Waals forces due to its gaseous state, which allows it to remain a gas at room temperature.
- In contrast, sulphur has stronger intermolecular forces due to its larger size and the nature of its bonding, which results in it being a solid at room temperature.

5. **Conclusion**:
- Based on the analysis above, the statement "Oxygen is a gas but sulphur is a solid" is **True**.

### Final Answer:
**True**

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