Question

In a radioactive process, Atoms decay some particle which may or may not change the atomic number of the atoms. Which of the following particles must change the atomic number of the radioactive element?
I. $\alpha$-decay
II. $\beta$-decay.
III.$\gamma$-decay

• A. I only
• B. II only
• C. III only
• D. I and II only
• E. I,II, and III

Answer 1

The correct option is D I and II only

In an alpha decay, a helium nucleus(${}_2^{4}He$) is released. Thus the atomic number of the parent nucleus decreases by two.

In a beta decay, and electron(${}_{-1}^{0}e$) is released which increases the atomic number of parent nucleus by one.

However, in a gamma decay, one energy in form of photons is released, without changing the atomic number of parent species.