Ncert Exercises & Solutions

18. Which of the following statements are correct?

(a) Helium has the highest first ionisation enthalpy in the periodic table

(b) Chlorine has less negative electron gain enthalpy than fluorine

(d) In any period, atomic radius of alkali metal is the highest

(a, c, d)

Chlorine has more negative electron gain enthalpy than fluorine. Therefore, all other given statements are correct.