Question

The particles not emitted by radioactive substances are :
a.) gamma rays
b.) electrons
c.) protons
d.) He nuclei

Answer 1

Hint: The radioactive substances are those which have unstable nuclei. As a result, this nuclei disintegrate to form a stable nuclei and some energy is emitted with different kinds of rays. Basically, three types of decay occur, the alpha decay giving alpha particles, beta decay giving beta particles and gamma decay giving gamma particles.

Complete step by step answer:
First we need to understand What the radioactivity is.
The radioactivity may be defined as the process in which some particles are emitted from the nuclei of an atom due to nuclear instability. The material with unstable nuclei is called the radioactive substances.
There are three types of radioactive decays that are commonly studied. Let us see them one by one.
The first one is the alpha decay. During this decay, the nucleus emits alpha particles. The alpha particles are the helium nucleus.
The second type of decay is the beta decay. During this decay, the nucleus emits an electron or a positron.
The third type of common decay is the gamma decay which involves the emission of gamma particles.
As we are done with the background work.
So, now observing the options we see that the option a.) contains gamma rays. This is emitted in gamma decay. So, this is not the correct answer.
The option b.) is the electrons. The electrons are emitted in beta decay. So, this is also not the correct option.
The option c.) is the protons. The protons are not emitted in any of the decay. So, the option c.) could be the answer.
The option d.) is the helium nucleus. The helium nucleus are the alpha particles which are emitted in alpha decay. So, even the option d.) is not the correct answer.
So, the correct answer is “Option C”.

Note: The alpha particle is the helium nucleus. This means that an alpha particle contains two protons and two neutrons only. The two electrons are donated giving it +2 charge.
The protons are different from alpha particles. One can relate it that
mass of an alpha particle = 2 $ \times $ mass of a proton