Question

An atomic nucleus A is composed of 84 protons and 128 neutrons.

1. The nucleus A emits an alpha particle and is transformed into nucleus B. What is the composition of nucleus B?
2. The nucleus B emits a beta particle is transformed into nucleus C. What is the composition of nucleus C?
3. Does the composition of nucleus C change if it emits gamma radiations?

1. An atomic nucleus A is composed of 84 protons and 128 neutrons. The nucleus A emits an α-particle and is transformed into a nucleus B. What is the composition of B?
2. The nucleus B emits a β-particle and is transformed into a nucleus C. What is the composition of C?
3. What is the mass number of the nucleus A?
4. Does the composition of nucleus C change if it emits the γ radiation?

Answer 1

1. The composition of B is 82 protons and 126 neutrons.
   The resultant nucleus B has two protons and two neutrons fewer than the initial nucleus when nucleus A emits an α-particle.
2. The composition of C is 83 protons and 125 neutrons.
   Nucleus C has one more proton and one fewer neutron than nucleus B when the latter emits a β-particle.
3. The mass number of nucleus A = number of protons + number of neutrons = 84 + 128 = 212.
4. No, the composition of nucleus C does not change on emitting γ radiations as there is no change in the mass number A and atomic number Z of the nucleus in gamma emission.