Question

21. What changes occur to the atomic number and mass of a nucleus during each of the following decay scenarios: α particle is emitted
a. The atomic number decreases by two and the mass number decrease by four

b. The atomic number increases by one and the mass number remains unchanged

c. The atomic number and mass number remain unchanged.

d. The atomic number decreases by one and the mass number remains unchanged

e. The atomic number decrease by one and the mass number remains unchanged.

Answer 1

Answer: The correct answer is Option a.

Explanation:

Alpha decay is defined as the decay process in which alpha particle is released. In this process, a heavier nuclei decays into a lighter nuclei. The alpha particle released carries a charge of +2 units and a mass of 4 units.

The released alpha particle is also known as helium nucleus.

In this decay process, the atomic number of the atom decreases by 2 units and the mass number decreases by 4 units.

The chemical equation for alpha decay process follows:

$_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}\textrm{Y}+_2^4\alpha$

Hence, the correct answer is Option a.