Which of the following statements are correct ?
(I) Helium has the highest first ionisation enthalpy in the periodic table
(II) Chlorine has less negative electron gain enthalpy than fluorine
(III) Mercury and bromine are liquids at room temperature
(IV) In any period among representative elements, atomic radius of alkali metal is the highest
Chlorine has more negative electron gain enthalpy than fluorine.
All other given statements are correct.