Question

Which of the following radioactive particle are decayed in the reaction ${}_{85}^{218}At{\to }_{83}^{214}Bi$+ ${}_Z^{A}X$.

• A. alpha
• B. ${\beta }^{-}$
• C. ${\beta }^{+}$
• D. electron capture
• E. gamma

Answer 1

The correct option is A alpha

The given reaction: ${}_{85}^{218}At{\to }_{83}^{214}Bi$ $+$ ${}_Z^{A}X$

In a nuclear reaction, mass number and the atomic number are conserved.

$\therefore$ $218=214+A$ $⟹A=4$

Also, $85=83+Z$ $⟹Z=2$

Thus, the decayed particle is ${}_2^{4}He$ (alpha particle).