Question

WHY ELECTRON AFFINITIES O F ELEMENTS OF PERIOD 3 ARE HIGHER THAN THOSE OF CORRESPONDING ELEMENTS OF PERIOD 2 OF THE PERIODIC TABLE?

Answer 1

Because nuclear charge increases

Answer 2

all the factors which influence ionisation energy would also influence electron affinity or electron gain enthalpy like nuclear charge,screening or shielding effect by shells, penetration power of orbitals, stable configuration, atomic radius