Spot the odd property among d-block elements

Exercise and reference answers

Questions

1. Items

   1. Variable oxidation states
   2. Form coloured ions
   3. Form complexes
   4. Always +1 oxidation

   Reason

   d-block elements show MULTIPLE oxidation states, not just +1.

   Odd item

   Always +1 oxidation

2. Items

   1. Zn²⁺
   2. Cu²⁺
   3. Fe³⁺
   4. Sc³⁺

   Reason

   Zn²⁺ has a full d¹⁰ configuration so it is colourless; the others are coloured d-block ions.

   Odd item

   Zn²⁺