transitional elements

Question 1

explain why most iron complexes are coloured?

Answer 1

1. Fe ion has partially filled 3d orbitals
2. in the presence of ligands, they are split into 2 groups w/ small energy gap
3. wavelength of light energy from visible region is used to excite an e- from 3d orbital of lower energy partially fill …

Question 2

Explain why so many TE are coloured. [3]

Answer 2

1. In the presence of ligands, the partially filled d orbitals split into 2 energy levels with a small energy gap
2. In the presence of visible light, a d electron
   in a d orbital of lower energy absorbs energy from visible light region
3. and is promoted to the higher energy d orbital via d-d electronic transition
4. The complementary colour is observed

Question 3

state the property, typical of TE, which allows (eg. Fe2+(aq)) to behave as a catalyst in this reaction

Answer 3

variable oxidation states