Neptunium-237 decays by a series of steps to bismuth-209. How many α and β particles are produced by this decay process?

Verified step by step guidance

1. Step 1: Understand the decay process. Neptunium-237 (Np-237) decays to Bismuth-209 (Bi-209) through a series of alpha (α) and beta (β) decays. An alpha decay reduces the atomic number by 2 and the mass number by 4, while a beta decay increases the atomic number by 1 without changing the mass number.
2. Step 2: Determine the change in mass number. The initial mass number is 237 (for Np-237) and the final mass number is 209 (for Bi-209). Calculate the total change in mass number: 237 - 209 = 28.
3. Step 3: Calculate the number of alpha decays. Each alpha decay reduces the mass number by 4. Divide the total change in mass number by 4 to find the number of alpha decays: 28 / 4 = 7 alpha decays.
4. Step 4: Determine the change in atomic number. The initial atomic number of Neptunium is 93, and the final atomic number of Bismuth is 83. Calculate the total change in atomic number: 93 - 83 = 10.
5. Step 5: Calculate the number of beta decays. Each alpha decay reduces the atomic number by 2, so 7 alpha decays reduce it by 14. To reach a total change of 10, beta decays must increase the atomic number by 4. Therefore, 4 beta decays are needed.

Key Concepts

Radioactive Decay

Radioactive decay is the process by which unstable atomic nuclei lose energy by emitting radiation. This can occur in various forms, including alpha (α) and beta (β) decay. Understanding the type of decay is crucial for predicting the products and the number of particles emitted during the decay process.

Alpha and Beta Particles

Alpha particles consist of two protons and two neutrons, making them relatively heavy and positively charged. They are emitted during alpha decay, resulting in a decrease in the atomic number by two. Beta particles, on the other hand, are high-energy, high-speed electrons or positrons emitted during beta decay, which changes a neutron into a proton or vice versa, affecting the atomic number by one.

Decay Series

A decay series is a sequence of radioactive decay processes that an unstable nucleus undergoes until it reaches a stable state. Each step in the series can involve different types of decay, leading to the production of various daughter isotopes. Analyzing the decay series of neptunium-237 to bismuth-209 helps determine the total number of alpha and beta particles emitted throughout the entire decay process.