Question

describe the bonding present in
(a) solid krypton, 36Kr
(b) solid rubidium, 37Rb
use your description of their bonding to explain why the boiling point of krypton is -152degreescelcius whereas that of rubidium is 686degreescelcius despite having the same relative atomic mass

Answer 1

The rubidium atoms in solid rubidium are bound by fairly strong metallic bonds. The monoatomic krypton molecules are bound by weak intermolecular (Van der Waals) forces. Therefore, the boiling point of rubidium is much higher than the boiling point of krypton despite having the same relative atomic mass.