Nuclear Equations for Alpha and Beta Decay

Introduction

A nuclear equation illustrates the outcome when a radioactive nucleus undergoes decay.
Focus on alpha and beta decay, and understanding how to write nuclear equations for them.

Alpha Particle Characteristics
- Composed of 2 protons and 2 neutrons.
- Symbolized by the helium nucleus (He), with atomic number 2 and mass number 4.
Alpha Decay Process
- Illustrated using the example of radium decaying into radon.
- Atomic Number:
  - Radium starts with atomic number 88.
  - The alpha particle contributes 2 protons.
  - Atomic number of radon = 88 - 2 = 86.
- Mass Number:
  - Initial mass number of radium is 226.
  - Mass number of the alpha particle is 4.
  - Mass number of radon = 226 - 4 = 222.
Rules for Alpha Decay
- Atomic number decreases by 2.
- Mass number decreases by 4.
Example Problem
- Americium to neptunium decay.
- Atomic Number:
  - Americium = 95.
  - Alpha particle = 2.
  - Neptunium = 95 - 2 = 93.
- Mass Number:
  - Americium = 241.
  - Alpha particle = 4.
  - Neptunium = 241 - 4 = 237.

Beta Decay Process
- A neutron in the nucleus transforms into a proton and an electron (beta particle).
- Example: Aluminum changes to silicon.
- Atomic Number:
  - Increases by 1 due to an additional proton.
  - Silicon's atomic number becomes 14.
- Mass Number:
  - Remains unchanged as the total number of protons and neutrons stays the same.
Rules for Beta Decay
- Atomic number increases by 1.
- Mass number remains the same.
Example Problem
- Iodine turning into xenon.
- Atomic Number:
  - Iodine increases by 1.
  - Xenon = 54.
- Mass Number:
  - Remains 131.

Unlike alpha and beta decay, gamma decay does not alter the atomic or mass numbers.

Understanding nuclear equations aids in identifying changes in atomic and mass numbers during decay.
Reference questions and problems available in the revision workbook.