The radioactive nucleus undergoes a series of decay according to the scheme (given below). If the mass number and atomic number of A are 180 and 72 respectively, then what are these numbers for A4 ?
Correct answer: A. 172 and 69
- A. 172 and 69
- B. 172 and 70
- C. 174 and 70
- D. 176 and 70
Explanation
In alpha decay, the atomic number decreases by 2 and the mass number decreases by 4 due to the emission of an alpha particle. In beta-minus decay, the atomic number increases by 1 while the mass number remains the same due to the emission of an electron. In gamma decay, there are no changes in atomic number or mass number. The equations would be:18072A → 17670A1 → 17671A2 → 17269A3 → 17269A4
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Atomic nuclei contain protons and neutrons, with nuclear size, mass defect and binding energy describing their stability. The work covers alpha, beta and gamma decay, decay equations, half-life and decay rate, along with radiation safety and medical applications such as imaging, radiotherapy and tracers.
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