Question

Write a short note on the paramagnetic behaviour and formation of coloured ions of transition elements.

Hint:

The paramagnetic nature of transition elements depends on unpaired electrons, while colour formation is due to d-d transitions.

Answer 1

Step 1: Paramagnetic Behaviour: - Transition metals exhibit paramagnetism due to the presence of unpaired electrons in d-orbitals. - Magnetic moment: \[ \mu = \sqrt{n(n+2)} \text{ BM} \] where \( n \) is the number of unpaired electrons. 

Step 2: Formation of Coloured Ions: - Colour in transition metal ions arises due to d-d transitions when electrons absorb visible light and jump between d-orbitals. - Example: \[ [Cu(H_2O)_6]^{2+} \text{ (Blue)} \]