Question

1. Describe alpha decay. Does the mass number change? 2. Describe beta decay. Does the mass number change? 3. What is a positron? 4. Describe gamma decay. 5. What type of decay is occurring in the beryllium example Be Li+ºje 6. What type of decay is occurring in the uranium example 238,0 – 23400 Th+"He? 7. What type of decay is occurring in the iodine example 131531 → 13154Xe+ºje 8. What type of decay is occurring in the radon example 22286Rn –218. Po+42He 9. Why is Po named Polonium?

Answer 1

1) In alpha decay, an energetic helium ion (alpha particle) is ejected, leaving a daughter nucleus of atomic number two less than the parent and of atomic mass number four less than the parent. Therefore, mass number changes.

2) In beta decay, an energetic negative electron is emitted, producing a daughter nucleus of one higher atomic number and the same mass number. Mass number does not change.

3) In beta-plus decay an energetic positron is created and emitted, along with a neutrino, and the nucleus transforms to a daughter, lower by one in atomic number and the same in mass number.

4) Gamma emission (γ emission) is observed when a nuclide is formed in an excited state and then decays to its ground state with the emission of a γ ray, a quantum of high-energy electromagnetic radiation. There is no change in mass number or atomic number during the emission of a γ ray unless the γ emission accompanies one of the other modes of decay.

5) Positron decay

6) Alpha decay

7) Beta decay

8) Alpha decay

9) Named for the country of poland.