Question

what is the missing particle?
198 86 rn → 4 2 he + ?
194 84 po 194 84 rn 196 84 po

Explanation:

Step1: Calculate the mass number of the missing particle

The mass number of \(^{198}_{86}\text{Rn}\) is \(198\), and the mass number of \(^{4}_{2}\text{He}\) is \(4\). Let the mass number of the missing particle be \(A\). Then \(A = 198 - 4=194\).

Step2: Calculate the atomic number of the missing particle

The atomic number of \(^{198}_{86}\text{Rn}\) is \(86\), and the atomic number of \(^{4}_{2}\text{He}\) is \(2\). Let the atomic number of the missing particle be \(Z\). Then \(Z = 86 - 2 = 84\).

Step3: Identify the element

The element with atomic number \(84\) is Polonium (\(Po\)).

Answer:

\(^{194}_{84}\text{Po}\)