Question

of the two isotopes ${}^{173}Au$ and ${}^{199}Au$ the correct statement is

• A. ${}^{199}Au$ decays by deta emission and ${}^{173}Au$ decays alpha emission
• B. ${}^{199}Au$ decays by alpha emission and ${}^{173}Au$ decays by deta emission
• C. Both decays by alpha emission
• D. Both decays by deta emission

Answer 1

Answer: (A)

${}^{199}Au$ decays by deta emission and ${}^{173}Au$ decays alpha emission

${}_{79}^{173}{A}_u$ will decay in alpha emission

${}_{79}Au173{\to }_2^4\alpha {+}_{77}{I}^{169}$

${}_{79}A{u}^{199}$ will decay in $\beta$ emission

${}_{79}A{u}^{199}\to {}_{-1}^0\beta {+}_{80}H{g}^{199}$