Question

Describe the variability of oxidation states in the first row of the transition elements (Sc-Cu) and indicate the general trend.

Answer 1

1. First row transition elements (Sc to Cu) show multiple oxidation states due to involvement of both 4s and 3d electrons in bonding.
2. The usual oxidation states arise from losing 4s electrons (+2 state is common), and higher states occur by involving 3d electrons (+3, +4, etc.).
3. Scandium mainly shows +3, while elements like Mn exhibit a wide range (+2 to +7) due to stable half-filled configurations.
4. The oxidation state variability tends to increase from left to right, then decreases towards Cu and Zn.
5. Cu shows +1 and +2 oxidation states, with +2 more common, while Zn mostly shows +2.
6. Overall, the general trend is: lower oxidation states (+2) for early elements become stable, and higher oxidation states appear in the middle of the series, decreasing again towards the end.