During beta-particle emission, a neutron splits into _______?

a proton and an electron
two protons
two electrons
two neutrons

three answers are nonsense, and violate conservation of mass.

During beta-particle emission, a neutron splits into a proton and an electron.

During beta-particle emission, a neutron transforms into a proton and releases a beta particle. Therefore, the correct answer is "a proton and an electron." To understand why, we need to examine the process of beta decay.

In beta decay, a neutron inside an atomic nucleus undergoes a transformation. The weak nuclear force is responsible for this process. During beta-minus decay (β- decay), a neutron transforms into a proton, emitting a high-energy electron called a beta particle (β-). The beta particle carries away the excess energy and negative charge.

So, to answer the question, a neutron splits into a proton and an electron during beta-particle emission.