Question

Fluorine and chlorine are gases .Bromine is liquid whereas Iodine is solid.Discuss

Answer 1

Dear Student,

The reason is that on moving down a group the attractive forces( van der wall forces ) increases which is due to the increase in size of the atoms and the molecular weight. As, the size increases intermolecular forces also increase and hence it is weakest in fluorine and chlorine so exist in gaseous form, less weaker in bromine so exist in liquid form and strongest in iodine so it exist as solid form at ordinary temperature.

Regards.