Question

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

Explanation:

Step1: Calculate mass number

Mass number of missing particle: \(198 - 194=4\)

Step2: Calculate atomic number

Atomic number of missing particle: \(86 - 84 = 2\)

Step3: Identify particle

Particle with mass number \(4\) and atomic number \(2\) is \(^4_2He\)

Answer:

\(^4_2He\) (the third option)