1. According to the nuclear shell model, the order in which quantum energy levels are filled with protons in nuclei of successive elements in the periodic table is as shown in the figure. A similar arrangement holds for the neutrons. energy levels multiplicity of states 197/2 8 1g 1gaz 10 2p1/2 2p 1f 0264 2s 1d 1f5/2 2p3/2 1f7/2 1d3/2 251/2 1ds/2 8 1p 1s 1p1/2 1paz 426 24 151/2 2 (a) Answer each of the following questions with one or two sentences: (i) What is the main assumption of the nuclear shell model? (ii) State what is indicated by the symbols s, p, d, f, and g. (1 mark each) (iii) What interaction is causing the splitting of the energy levels? What is the quantum number indicated by the subscripts 1/2, 3/2 etc.? (iv) Explain the multiplicity of states in the figure. (v) What is the effect of the Pauli exclusion principle in the filling of the energy levels? (vi) Why are the energy levels of the protons slightly higher than the energy levels for the neutrons? (vii) What is meant by magic numbers? List the sequence of the first 5 magic numbers.