Question

The mass of neutron is of the order of:
A) \[{{10}^{-27}}kg\]
B) \[{{10}^{-28}}kg\]
C) \[{{10}^{-25}}kg\]
D) \[{{10}^{-24}}kg\]

Answer 1

Hint: The neutron is a subatomic particle, with the symbol n, it has no electric charge and a mass slightly greater than that of a proton. Neutrons along with protons constitute the nuclei of atoms.

Complete answer:
> The chemical properties of an atom are mostly determined by the electronic configuration of the electrons in the orbit of the atom and the electron configuration is determined by the charge of the nucleus, set by the number of protons or atomic number.
> Neutrons do not affect the electron configuration, but the sum of protons and the number of neutrons together defines the mass of the nucleus.
> It is a neutral subatomic particle with a rest mass of \[1.67493\times {{10}^{-27}}kg\], its mass is almost same as proton, \[1.6726\times {{10}^{-27}}kg\] to be precise.
> As the mass of the neutron is \[1.6743\times {{10}^{-27}}kg\], we can see that its order is \[{{10}^{-27}}kg\].
To understand it better, we can represent it pictorially as-

Electron	Proton	Neutron
\[9.1~\times {{10}^{-31}}kg\]	\[1.6726231\times {{10}^{-27}}kg\]	\[1.6749286\times {{10}^{-27}}kg\]

Therefore, the correct answer is option a) \[{{10}^{-27}}kg\].

Additional Information When a chemical element differs only in the number of neutrons it is called an isotope, for example carbon with atomic number 6 has the abundant carbon-12 isotope and a rare carbon isotope with 7 neutrons.
Free neutrons can cause ionizing radiations as such that they can be biological hazards depending upon the dose.

Note: Similarly, if we talk about electrons:
Electrons are the subatomic particles that orbit the nucleus of an atom. They are generally negative in charge and are much smaller than the nucleus of the atom. Its mass is \[9.1\times {{10}^{-31}}kg\] and its order is \[{{10}^{-31}}\].
A proton is a subatomic particle with a positive charge. It is found in the atomic nucleus. Its mass is \[1.67\times {{10}^{-27}}kg\], which is an order of \[{{10}^{-27}}\].