Question

In order for a nucleus of an atom to exhibit the NMR phenomenon, it must consist of

A. an odd number of protons

B. an odd number of protons and neutrons

C. an odd number of neutrons

D. any one of the compositions described in a, b, and c

Answer 1

Ans- D. any one of the compositions described in a, b, and c

All nuclei have a property called spinning, which describe the nature of the nucleus magnetic field. Spin is characterize by I, which is the spin quantum number. Only nuclei with spin quantum number, I ≠ 0 can absorb/ emit EMR in radiowave region. Nuclei with I=0, denotes no nuclear spin.

            SQN (I) is associated with mass no. & atomic number of the nuclei.

• When there are odd number of neutrons and odd number of protons in the nucleus, it will have an integer value of spin (i.e.- 1, 2,3)
• If sum of the number of protons and neutrons is odd number, the nucleus will have a half integer spin (i.e.- ½, 3/2, 5/2)