when d-block ions are surrounded by ligands the differences in shape split 3d orbitals into 2 different energy levels
electrons tend to occupy lower energy level but when they react they absorb energy in visible light region of EM spectrum, become excited and move to upper energy level
as they move back down to original energy level they release energy
quantum theory and energy jump
there's a fixed relationship between size of energy 'jump' and wavelength of radiation absorbed
why are some d-block compounds white or colouless?
there's a larger energy gap between 3d orbitals so radiation absorbed is in UV region of EM spectrum
3d surbshell is full or partially filled so electrons can't move to upper energy level
energy gap between d orbitals depends on
oxidation number of central ion
ligands
coordination number
colours of compounds
some frequencies of light are absorbed (due to splitting of 3d orbitals)
the rest are transmitted/reflected - frequencies combine to make the complement of the colour of the absorbed frequencies which is what we see
