Question

List-I shows different radioactive decay processes and List-II provides possible emitted particles. Match each entry in List-I with an appropriate entry from List-II, and choose the correct option.

	List-I		List-II
(P)	\(^{238}_{92}U → ^{234}_{91}Pa\)	(1)	one 𝛼 particle and one 𝛽+ particle
(Q)	\(^{214}_{82}Pb → ^{210}_{82}Pb\)	(2)	three 𝛽− particles and one 𝛼 particle
(R)	\(^{210}_{81}Tl → ^{206}_{82}Pb\)	(3)	two 𝛽− particles and one 𝛼 particle
(S)	\(^{228}_{91}Pa → ^{224}_{88}Ra\)	(4)	one 𝛼 particle and one 𝛽− particle
		(5)	one 𝛼 particle and two 𝛽+ particles

• A. P →4, Q→ 3, R →2, S →1
• B. P →4, Q→ 1, R →2, S →5
• C. P →5, Q→ 3, R →1, S →4
• D. P →5, Q→ 1, R →3, S →2

Answer 1

The Correct Option is A

To solve the problem, we match each radioactive decay process from List-I with the appropriate emitted particles from List-II by analyzing the changes in atomic and mass numbers for each transformation. Let's examine each decay: 

• (P) \(^{238}_{92}U → ^{234}_{91}Pa\): The decrease in mass number from 238 to 234 indicates that an alpha particle (\(\alpha\), \(^{4}_{2}He\)) is emitted, reducing the atomic number by 2 and the mass number by 4. Additionally, the atomic number decreases further by 1 (not entirely from \(\alpha\)), suggesting the emission of a beta minus particle (\(\beta^-\)), which increases the atomic number by 1. Therefore, one \(\alpha\) and one \(\beta^-\) particle are emitted. This matches with (4) one \(\alpha\) particle and one \(\beta^-\) particle.
• (Q) \(^{214}_{82}Pb → ^{210}_{82}Pb\): The mass number decreases by 4 with no change in atomic number, suggesting the emission of an alpha particle (\(^{4}_{2}He\)), which also results in the release of two beta minus particles (\(\beta^-\)), since only alpha would reduce atomic number by 2. This matches with (3) two \(\beta^-\) particles and one \(\alpha\) particle.
• (R) \(^{210}_{81}Tl → ^{206}_{82}Pb\): The mass number decreases by 4 and atomic number increases by 1. This implies the emission of an alpha particle and three beta minus particles (\(\beta^-\)), as one would increase atomic number by four. This matches with (2) three \(\beta^-\) particles and one \(\alpha\) particle.
• (S) \(^{228}_{91}Pa → ^{224}_{88}Ra\): The mass number decreases by 4, and atomic number decreases by 3, indicating one alpha particle, reducing atomic number by 2 and perhaps a beta plus particle (\(\beta^+\)), reducing number by 1. This matches with (1) one \(\alpha\) particle and one \(\beta^{-}\) particle.

Thus, the correct matching is P → 4, Q → 3, R → 2, S → 1.