Consider the following radioactive decay process ${ }_{84}^{218} A \xrightarrow{\alpha} A_{1} \xrightarrow{\beta} A_{2} \xrightarrow{\gamma} A_{3} \xrightarrow{\alpha} A_{4} \xrightarrow{\beta^{+}} A_{5} \xrightarrow{\gamma} A_{6}$ The mass number and the atomic number $\mathrm{A}_{6}$ are given by :

JEE Main · 2023 · 24 Jan 2023 · Shift 1 · Modern Physics

Consider the following radioactive decay process

_{84}^{218} A α A_{1} β A_{2} γ A_{3} α A_{4} β^{+} A_{5} γ A_{6}

The mass number and the atomic number

A_{6}

are given by :

(A)210 and 82
(B)210 and 84
(C)210 and 80✓ Correct
(D)211 and 80

Answer: (C)

Solution

Begin with

_{84}^{218} A

. An

α

emission strips

4

from the mass number and

2

from the charge, leaving

_{82}^{214}

; a

β^{-}

then raises the charge by one to

_{83}^{214}

, while the following

γ

changes neither. A second

α

brings it to

_{81}^{210}

, a

β^{+}

lowers the charge to

_{80}^{210}

, and the final

γ

leaves it unchanged. The last nucleus has mass number

210

and atomic number

80

JEE Main · 2023 · 24 Jan 2023 · Shift 1 · Single correct option

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