The first ionization enthalpies of Mg and Al can be expected to be

The first ionization enthalpies of Mg and Al can be expected to be
  1. IE1(Mg)=577.5 kJ·mol-1,IE1(Al)=577.5 kJ.mol-1
  2. IE1(Mg)=577.5 kJ.mol-1,IE1(Al)=737.7 kJ.mol-1
  3. IE1(Mg)=737.7 kJ.mol-1,IE1(Al)=737.7 kJ.mol-1
  4. IE1(Mg)=737.7 kJ.mol-1,IE1(Al)=577.5 kJ.mol-1

Solution

Magnesium has the atomic number of 12. It has the electronic configuration of Ne3s2. It has the fully filled orbitals. So, it has the high ionisation energy. The atomic number of the aluminium is 13. It has the electronic configuration of Ne3s23p1. It has the low value of the first ionisation energy. So, the first ionisation energy of magnesium is higher than the aluminium because magnesium has the fully filled orbital. Hence, The first ionization enthalpies of Mg and Al can be expected to be IE1(Mg)=737.7 kJ.mol-1,IE1(Al)=577.5 kJ.mol-1.

Asked in: AP EAMCET 2021 (20 Aug Shift 2)

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