coloured ions TM

Question 1

explain how colour arises

Answer 1

ligands cause some electrons in the 3d orbital to gain more energy and this splits the 3d orbitals into two different energy levels.

electrons tend to occupy lower energy level, so they absorb energy from visible light and jump to the excited state.

amount of energy depends on central ion and ligands

certain wavelengths are absorbed and the rest are reflected and the colour is the complementary colour to the one absorbed

Question 2

planck’s constant

Answer 2

change in energy = h x v = (h x c)/lamda where h is planck’s constant and c is the speed of light 3x10 to the 8 and lamda is wavelength and v is frequency

Question 3

why are some colourless

Answer 3

empty 3d sub level or full 3d sub level so no electrons will jump so nothing absorbed so all light refelcted

Question 4

explain colorimetry

Answer 4

white light shone through filter which only lets colour of light which gets absorbed by complex through and this is absorbed in the sample and the colorimeter calculates how much was absorbed as it passed through the sample.

before doing so you must produce a calibration curve by measuring absorbance of known concentrations of solutions and plotting a graph