Question

Which particle is emitted during beta-minus decay?

• A. Proton
• B. Neutron
• C. Positron
• D. Electron

Hint:

In \( \beta^- \) decay, the Atomic Number (\( Z \)) increases by 1, but the Mass Number (\( A \)) remains the same.
In \( \beta^+ \) decay, the Atomic Number (\( Z \)) decreases by 1.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Beta decay is a type of radioactive decay in which a beta particle is emitted from an atomic nucleus. There are two types: beta-minus (\( \beta^- \)) and beta-plus (\( \beta^+ \)).
Step 2: Key Formula or Approach:
The nuclear reaction for \( \beta^- \) decay is:
\[ {}_Z^A X \rightarrow {}_{Z+1}^A Y + e^- + \bar{\nu}_e \]
Where:
\( n \rightarrow p + e^- + \bar{\nu}_e \)
A neutron transforms into a proton, an electron, and an anti-neutrino.
Step 3: Detailed Explanation:
In \( \beta^- \) decay, the nucleus has too many neutrons. To achieve stability, a neutron is converted into a proton. During this process, a high-energy electron (called a beta particle) and an electron antineutrino are ejected from the nucleus.
Note that the electron is not one of the orbital electrons; it is created and ejected directly from the nucleus.
In contrast, \( \beta^+ \) decay emits a positron.
Step 4: Final Answer:
The particle emitted during beta-minus decay is an electron.