Explain why transition metal compounds are often coloured in solution.
The valence electrons of transition metals are found in d-orbitals. When the metal ion forms a complex with ligands the d-orbitals split into two different energy levels, and the gap between these levels happens to correspond with that of visible light.
This means that when the electrons in the lower level are promoted to the higher level part of the visible spectrum is absorbed - leading to the reflected light being coloured.
PD
Related Chemistry A Level answers
All answers ▸Palladium acts as a heterogeneous catalyst in the reaction between an alkene with hydrogen by providing an alternative reaction route. Describe the stages of this reaction route. (3 marks)
What are the oxidation numbers of each element in these examples: a) H2SO4 b) N2 c) NH4+
How could you obtain a carboxylic acid from oxidation of an alcohol and what type of alcohol would be suitable?
Part 2: from the empirical formula, calculate the molecular formula if the molecular weight of the substance is 180 g/mol