Question

in the uranium-235 natural decay series, the uranium-235 initially undergoes alpha decay, the resulting daughter emits a beta particle, and the succeeding daughters emit an alpha and a beta particle in that order. write the four nuclear decay equations, one to represent each of the first four steps in the uranium-235 decay series.

Answer 1

In the uranium-235 decay series, the first four steps involve the emission of alpha particles in the first and third steps and beta particles in the second and fourth steps, resulting in the transmutation of elements and decreasing the uranium's atomic mass.

Uranium-235 Decay Series

The decay series of uranium-235 begins with the initial nucleus undergoing alpha decay. Following are the first four steps in this decay series:

1. Uranium-235 to Thorium-231:
   235U → 4He + 231Th
2. Thorium-231 to Protactinium-231:
   231Th → 0−β + 231Pa
3. Protactinium-231 to Actinium-227:
   231Pa → 4He + 227Ac
4. Actinium-227 to Thorium-227:
   227Ac → 0−β + 227Th

In the above equations, alpha particles (α) are emitted in the first and third steps, reducing the atomic number by 2 and mass number by 4 each time. In the second and fourth steps, beta particles (β) are emitted, increasing the atomic number by 1 without changing the mass number.