Question

During a negative beta decay
A. An atomic electron is ejected
B. An electron which is already present within the nucleus is ejected
C. A neutron in the nucleus decays emitting an electron
D. A part of the binding energy of the nucleus is converted into an electron.

Answer 1

Hint: Beta decay is a radioactive decay in which a neutron is converted into a proton or an electron by emission of a beta particle (an electron or a positron). When the emitted beta particle is an electron, it is called negative beta decay.

Complete step by step answer:
Unstable nucleus undergoes radioactive decay to obtain a stable configuration.
Radioactive decay of a nucleus is the process in which the nucleus loses energy in the form of radiations. Therefore, this kind of decay is also called nuclear decay.
One type of the radioactive decay is beta decay. In beta decay, a neutron of the nucleus is converted into a proton or an electron by emission of a beta particle. A beta particle can be an electron or a positron.
When the neutron is converted into an electron, the beta particle released is a positron. Along with the positron, a neutrino is also released. This type of beta decay is called positive beta decay. It is denoted by ${\beta }^{+}$.
The equation of positive decay is as follows:
$p\to n+e^{+}$
When the neutron is converted into a proton, the beta particle released is an electron. Along with the electron, an anti-neutrino is also released. This type of beta decay is called negative beta decay. It is denoted by ${\beta }^{-}$.
The equation of negative decay is as follows:
$n\to p+e^{-}$
Therefore, now we know that negative beta decay involves decay of a neutron by emitting an electron.
Hence, the correct answer is option C.

Note:
Remember that the beta particle (electron or positron) and the neutrino (or anti-neutrino) are not present initially in the atom. They are produced during the process of the beta decay.
Therefore, the released electron cannot be an atomic electron.