Nuclear Chemistry - Result Question 5
####8. When a radioactive element emits successively one $\alpha$-particle and two $\beta$-particles, the mass number of the daughter element
[1999]
(a) is reduced by 4 units
(b) remains the same
(c) is reduced by 2 units
(d) is increased by 2 units
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Solution:
- (a) Mass number is affected by emmision of $\alpha$ particle while $\beta$-particle has negligible mass does not effect mass number. e.g.
$Z^{A} \xrightarrow{\alpha} Z-2 X^{A-4} \xrightarrow{\beta} Z-2+1 X^{A-4}$
$\xrightarrow{\beta} X^{A-4}$
