Group 1 Elements

Thermal Stability of Group 1 Hydroxides

Group 1 hydroxides are of the form , where is an alkali metal.

Concept:

The thermal stability of hydroxides increases down the group.

This is because as the size of the cation increases (from Li⁺ to Cs⁺), the polarizing power decreases. Lower polarizing power means less distortion of the OH⁻ ion, leading to greater thermal stability.

Therefore, the order is:

Correct Option: Option 1