Question

What is the missing particle?
231/90 th ---> _________ 231/91Pa

Answer 1

The missing particle in the given radioactive decay is a beta-particle denoted as
`-1e^0`. As a result of the decay, the atomic number increases by one unit while the mass number remains the same.

Step-by-step explanation:

In the given radioactive decay, the missing particle is a beta-particle denoted as
`-1e^0`. This is because, with beta decay, the atomic number increases by one unit while the mass number remains the same. In this case, the initial particle is 231/90 Th, and the final particle is 231/91 Pa.