Question

The study of radioactive decay results in the emission of particles, leading to four observations: (A) No change in atomic and mass number, (B) Atomic number decreases by 1, (C) Study of radioactive decay of unstable nuclei resulting in emission of a
particle leads us to four different observations listed below:
(A) Nochange in atomic number and mass number.
(B) Nochange in mass number but the atomic number decreases by 1.
(C) Nochange in mass number but the atomic number increases by 1.
(D) Atomic number decreases by 2 and the mass number decreases by 4.
Arrange the particles emitted in the above four cases in correct sequence:

• A. Alpha particle, positron, electron, photon
• B. Alpha particle, electron, positron, photon
• C. Photon, positron, electron, alpha particle
• D. Alpha particle, positron, photon, electron

Answer 1

The Correct Option is C

The task is to identify the particle emissions corresponding to alterations in atomic and mass numbers during radioactive decay. Let's analyze each observation and associate it with the appropriate particle emission:

(A) Atomic number and mass number remain unchanged: This is typical of gamma emission, which releases photons. Photons possess neither mass nor charge.

(B) Mass number remains unchanged, but the atomic number decreases by 1: This signifies positron emission, occurring when a proton transforms into a neutron with the emission of a positron.

(C) Mass number remains unchanged, but the atomic number increases by 1: This aligns with beta decay, where a neutron converts into a proton, emitting an electron (beta particle).

(D) Atomic number decreases by 2, and the mass number decreases by 4: This phenomenon is observed in alpha decay, characterized by the emission of an alpha particle (a helium nucleus).

Consequently, the correct sequence of emitted particles is: Photon, positron, electron, alpha particle.