Which of the following statements is incorrect? (a) I.E.1 of O is lower than that of N but I.E.2 O is higher than that of N (b) The enthalpy of N to gain an electron is almost zero but of P is 74.3 kJ mol-1 (c) isoelectronic ions belong to the same period (d) The covalent radius of iodine is less than its Van der Waal’s radius
Correct option is B) All isoelectronic ions belong to the same period of the periodic table, is a wrong statement as F − and Na + are isoelectronic but they belong to different periods. IE 1 of N is higher than that of O while IE 2 of O is higher than that of N due to stable half filled configuration. Van der Waal's radius of iodine is more than its covalent radius.
