Question

what is the missing particle?

$\begin{array} { c } { _ { 25 } ^ { 54 } m n ^ { * } } \
ightarrow { _ { 25 } ^ { 54 } m n } + ? end{array}$

Explanation:

Step1: Analyze mass number

In nuclear reactions, the mass number is conserved. The mass number of \(^{54}_{25}\text{Mn}^*\) is \(54\), and the mass number of \(^{54}_{25}\text{Mn}\) is also \(54\). Let the mass number of the missing particle be \(A\). Then \(54 = 54+A\), so \(A = 0\).

Step2: Analyze atomic number

The atomic number is also conserved. The atomic number of \(^{54}_{25}\text{Mn}^*\) is \(25\), and the atomic number of \(^{54}_{25}\text{Mn}\) is \(25\). Let the atomic number of the missing particle be \(Z\). Then \(25=25 + Z\), so \(Z = 0\).

Step3: Identify the particle

A particle with \(A = 0\) and \(Z = 0\) is a gamma ray (\(\gamma\)). The symbol for a gamma ray is \(^{\ 0}_{0}\gamma\).

Answer:

\(^{\ 0}_{0}\gamma\) (the third option in the given choices)