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

• A

  I, II and III are correct

• B

  I, III and IV are correct

• C

  II, III and IV are correct

• D

  All are correct