An atomic nucleus A is composed of 84 protons and 128 neutrons. The nucleus A emits and alpha particle and is transformed into a nucleus B.
(i) What is the composition of B ?
(ii) The nucleus B emits a beta particle and is transformed into a nucleus C. What is the composition of C?
(iii) What is mass number of the nucleus A ?
(iv) Does the composition of C change if it emits gamma radiations ?

Explanation

Let's solve the question step by step.

### Step 1: Determine the composition of nucleus B after the emission of an alpha particle from nucleus A.

- **Given:**
- Nucleus A has 84 protons and 128 neutrons.
- An alpha particle consists of 2 protons and 2 neutrons.

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