Emission of an alpha particle from a radioactive element.
Correct answer: D. Decreases its atomic number by 2 and decreases mass number by 4
- A. Increase its atomic number by 1 and decreases mass number by 2
- B. Increases its atomic number by 2 and decreases mass number by 2
- C. Decreases its atomic number by 1 and decreases mass number by 2
- D. Decreases its atomic number by 2 and decreases mass number by 4
Explanation
The alpha particle comprises of 2 neutrons and 2 protons so when an atom releases an alpha particle, it observes a drop in the atomic number by 2 representing the loss in protons, and a drop in the mass number by 4 corresponding to the loss of 4 nucleons (2 protons and 2 neutrons).
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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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