Understanding Alpha Decay
Alpha decay is a type of radioactive decay where an atom's nucleus emits an alpha particle. An alpha particle consists of 2 protons and 2 neutrons, which is essentially a Helium-4 nucleus (⁴He).
The Process
1. Parent Nucleus: Uranium-238 (²³⁸U) is the parent nucleus.
2. Alpha Particle Emission: It emits an alpha particle (⁴He).
3. Daughter Nucleus: The remaining nucleus after the alpha emission is the daughter nucleus.
Calculating the Daughter Nucleus
* Atomic Number: The atomic number (number of protons) decreases by 2 (because the alpha particle has 2 protons). Uranium has an atomic number of 92, so the daughter nucleus will have an atomic number of 90.
* Mass Number: The mass number (number of protons + neutrons) decreases by 4 (because the alpha particle has 4 nucleons). Uranium-238 has a mass number of 238, so the daughter nucleus will have a mass number of 234.
The Daughter Nucleus: Thorium-234
The daughter nucleus resulting from the alpha decay of Uranium-238 is Thorium-234 (²³⁴Th).
The Complete Decay Equation:
²³⁸U → ⁴He + ²³⁴Th
Important Note:
The daughter nucleus, Thorium-234, is also radioactive. It undergoes further decay through beta decay.
