(i) Name one halogen ,one metal ,and one 13 group element which is liquid at 30 o C. (ii) Compare the atomic size and ionization enthalpy of halogen group

Explanation:

Halogen : bromine

Metal : mercury

Group 13 element : gallium

These elements have higher ionization enthalpy. This value keeps on diminishing as we move down the group. This happens because of the increase in the size of the nucleus. fluorine has the highest ionization enthalpy than any other halogen.

Down the group, atom size increases. As a diatomic molecule, fluorine has the weakest bond due to repulsion between electrons of the small atoms.

the dissolution of polymer can be thermodynamically described in 2 steps.