Question

The second period element 'F' has less electron gain enthalpy than the third period element of the
same group for example 'Cr". Why​

Answer 1

Answer:

The negative electron gain enthalpy of fluorine os less than that of chlorine . It is due to small size if fluorine atom. As a result , there is strong interelectronic in the relatively small 2p orbital of fluorine and thus the incoming electron does not experience much attraction

Answer 2

Answer:

The second period element 'F' has less electron Gain enthalpy than the third period element of the same Group for example 'Cr' because the electrons arranged in an orbit due to the inter electronic repulsive force acts and it prevent the entry of new coming electron.