question_answer 13)

  Explain briefly how +2 oxidation state becomes more and more stable in the first half of the first row transition elements with increasing atomic number.

Answer:

In the elements of first half of the first row, with the removal of valance 4s electrons (+2 oxidation state) the 3d-orbitals get gradually occupied. Since the number of the empty d-orbitals decreases, the stability of the cations (M2+) increases from Sc2+ to Mn2+ .