Question

why are the colors of iron, iron 2 sulfate and iron3 oxide different?

Answer 1

colours changes due to different oxidation states of iron.The color of coordination complexes arises from electronic transitions between levels whose spacing corresponds to the wavelengths available in the visible light.the colors exhibited are related to the magnitude of the spacing between these levels.colour is also depend upon the unpaired electrons of metal.In the above case oxidation number of iron increases and it looses electrons.When the transition metals combine with other atoms, some of their electrons get more energy. When this occurs, the electrons absorb light of a given wavelength and this changes colour.