Question

How do spontaneous nuclear fission processes occur?

Answer 1

Spontaneous fission is generally a form of radioactive decay which is generally found in very heavy chemical elements. Whereas radioactive decay is the process in which an unstable atomic nucleus loses energy in the form of radiation.

Complete answer:
Material which has an unstable nucleus is termed as radioactive in nature. There are three most common types of decay which occur during the decay of nuclear processes. Spontaneous nuclear fission can occur by the emission of alpha and beta particles.
Alpha particle can be defined as a helium nucleus in this reaction heavier elements decay with the emission of alpha particles in which reaction can be shown as:
$^{238}{{U}_{92}}{{\to }^{234}}T{{h}_{90}}{{+}^{4}}H{{e}_{2}}$
Beta particle is generally an electron. This process can be described by converting a neutron to a proton and emitting a beta particle. Reaction can be shown as:
$^{32}{{P}_{15}}{{\to }^{32}}{{S}_{16}}{{+}^{0}}{{e}_{-1}}$
Other than alpha and beta particles there are two processes which also occur in nuclear fission which are known by the name positrons and gamma rays.
Positrons can be defined as the counterpart of an electron. Nuclei which have too many protons can decay by converting a proton to a neutron and emitting a positron. Reaction of positron can be represented as:
$^{8}{{B}_{5}}{{\to }^{8}}{{B}_{4}}{{+}^{0}}{{e}_{1}}$
Gamma rays are known as high-energy photons. When a nucleus emits an alpha or beta particle the new nucleus may have excess energy and this excess energy is released by emitting gamma rays. Reaction of this process can be shown as:
$^{234}T{{h}_{90}}{{\to }^{234}}P{{a}_{91}}{{+}^{0}}{{e}_{-1}}+\gamma$
Thus in this way spontaneous nuclear fission processes occur.

Note:
Three of the most common types of decay are alpha, beta and gamma decay all of which involve emitting one or more particles or photons. The weak force is the mechanism that is responsible for beta decay while the other two are done by the usual electromagnetic and strong forces