How many a particles and how many b particles are emitted in the 11-step decay of 235U into 207Pb?

Verified step by step guidance

1. Identify the type of decay processes involved in the transformation of uranium-235 (235U) to lead-207 (207Pb). These processes typically include alpha (α) decay and beta (β) decay.
2. Write down the nuclear reactions for each step of the decay sequence. In each alpha decay, the atomic number decreases by 2 and the mass number decreases by 4. In each beta decay, the atomic number increases by 1 while the mass number remains unchanged.
3. Count the number of alpha decays by observing the decrease in atomic number from uranium (Z=92) to lead (Z=82). Each alpha decay reduces the atomic number by 2.
4. Count the number of beta decays by observing the changes in neutron number (N) and accounting for the changes brought by alpha decays. Beta decay occurs when a neutron in the nucleus converts into a proton, emitting a beta particle and an antineutrino.
5. Verify the total number of alpha and beta decays by ensuring the final atomic and mass numbers match those of lead-207 (207Pb), with atomic number 82 and mass number 207.

Key Concepts

Nuclear Decay

Nuclear decay is the process by which an unstable atomic nucleus loses energy by emitting radiation. This can occur in various forms, including alpha (α) decay, beta (β) decay, and gamma (γ) decay. In the context of uranium-235 (235U), it primarily undergoes alpha decay, where it emits alpha particles, which consist of two protons and two neutrons.

Alpha Particles

Alpha particles are a type of ionizing radiation consisting of two protons and two neutrons, identical to a helium nucleus. They are emitted during the alpha decay of heavy elements like uranium. The emission of alpha particles reduces the atomic number of the parent nucleus by two, leading to the formation of a new element.

Decay Series

A decay series is a sequence of radioactive decay processes that a particular isotope undergoes until it reaches a stable end product. In the case of uranium-235 decaying to lead-207 (207Pb), the decay involves multiple steps, each characterized by the emission of particles, including alpha and beta particles, until a stable isotope is formed.