Question

metals of the second and third series have greater enthalpies of atomization than the corresponding elements of first series. Why?

Answer 1

Answer:

In first transition series, electrons are filled only in d orbitals but in second and third transition series, electrons are filled in d- and f-orbitals. ... Due to this enthalpy of atomization of second and third transition series elements are more than first transition series elements.

Answer 2

Metals of Second and Third series have greater enthalpies of atomization than first transition series because

of presence of D and F electrons.

• In first transition series, there are only D electrons present.
• While, in 2nd and 3rd transition series we have presence of D and F electrons.
• Hence, more the number of  subshells (d and f orbitals) having electrons, more the enthalpy of atomization.