The uranium isotopes U-236 and U-237 both emit radioactive particles. A nucleus of uranium-237 may be written as ²³⁷ ₉₂ U and emits a β⁻-particle. A nucleus of uranium-236 emits an α-particle. The number of protons in a nucleus of uranium is 92.

a. Describe the differences between an α-particle and a β⁻-particle.

b. Explain how uranium can exist in a number of different isotopes.

c. Write down the nuclear equation for the decay of U-236.