Question

Determine which decay process is being described in each case.

The atomic number deceases by one, and the atomic mass is unchanged.

The atomic number decreases by two, and the atomic mass decreases by four.

The atomic number increases by one, and the atomic mass remains unchanged.

Answer 1

1) Atomic number decreases by 1, mass unchanged — positron emission (β+ decay) (or electron capture).
Example: AZX → A(Z−1)Y + e+ + νe

2) Atomic number decreases by 2, mass decreases by 4 — alpha decay.
Example: AZX → A−4(Z−2)Y + 4 2He (α particle)

3) Atomic number increases by 1, mass unchanged — beta minus emission (β− decay).
Example: AZX → A(Z+1)Y + e− + ν̄e