Question

Predict a likely mode of decay for each of the following unstable nuclides.

Rh-92: beta decay or positron emission

Ga-60: beta decay or positron emission

S-27: beta decay or positron emission

Answer 1

The Nucleus of a atom consists oprotons and neutrons ·The number of protons and neutrons of the atom is determined by its atomic number (Z) and the difference between its mass number (4) and Z respectively. In equation form, The number of protons Z The number of neutrons (N) = A-Z A nucleus is said to be unstable, when it has either too high or too low N/Z value. A stable nucleus has N/Z value of 1 for Z value below 20, while moderately greater than 1 for Z value beyond 20. If the unstable nucleus possesses too high N/Z value then it undergoes beta decay mode, else emits positron until it attains stability Apply the above statement for each specified nucleus as follows: i. Rh 92: Z-45, А-92 N 92 45 47 N/Z 0.51

As N/Z is too less compared to the stability value, the nucleus emits positron. ii. Ga 60: Z 31, A 60 N 60-31 29 N/Z 0.483 As N/Z is too less compared to the stability value, the nucleus emits positron. iii.S- 27: Z 16, A 27 N 27-16-11 N/Z 0.6875 As N/Z is too less compared to the stability value, the nucleus emits positron