Question

The nuclei of tritium (${{H}^{3}}$) atom would contain neutrons
A. $1$
B. $2$
C. $3$
D. $4$

Answer 1

Hint: Neutrons are the subatomic particles detected in the nucleus. Neutrons combined with protons make up the mass number of the element. To find the neutron number of an isotope, tritium subtracts the atomic number or proton number from the atomic mass of the isotope.

Formula used: The general expression of any atom is represented by:
$_{Z}^{A}X$ ; here X is any atom.
Z is the number of protons.
A is the number of atomic masses.
Therefore, the number of neutrons, n $=(A-Z)$ .

Complete Step by Step Answer:
Atoms with the same number of protons but have different numbers of neutrons are called isotopes. Isotopes have different numbers of protons, so they have different numbers of neutrons. Neutrons are electrically neutral species. It plays an important role in the mass number and radioactive properties of atoms. Isotopes are generally formed when neutrons are added to the nucleus. But there is a little exception for protium, one of the isotopes of hydrogen, as it does not have any neutrons in its nucleus.
Hydrogen has 3 different isotopes termed protium ($_{1}^{1}H$), deuterium ($_{1}^{2}H$), and tritium ($_{1}^{3}H$). The nuclei of the neutron have $1$ proton number, $3$u mass number.
The number of neutrons, n $=A-Z$
Therefore, $n=(3-1)$
Or, $n=2$
Thus tritium, isotopes of hydrogen contain two neutrons.
Hence, option (B) is correct.

Note: The ability to possess isotopes by an element gives rise to the well-known phenomenon of radioactivity. For example, carbon has a proton number $6$and mass number $12$, so it has 6 neutrons. The addition of even one neutron can dramatically change a carbon isotope's properties. $_{6}^{14}C$ is unstable isotopes that undergo radioactivity.