Question

The most abundant isotope of hydrogen is:
A) Tritium
B) Deuterium
C) Protium
D) Para hydrogen

Answer 1

Isotopes are defined as the elements which have the same number of protons and electron or atomic numbers but different numbers of neutrons or atomic mass. Hydrogen exists in the three natural isotopes. These are Protium(hydrogen) ${{\text{ }}^{\text{1}}}\text{H }$, deuterium ${{\text{ }}^{2}}\text{H }$ and tritium ${{\text{ }}^{3}}\text{H }$. Hydrogen and deuterium are most stable isotopes of hydrogen.

Complete step by step answer:
Isotopes are defined as the elements which have the same number of proton and electron or atomic numbers but different numbers of neutrons or atomic mass.
Hydrogen exists in three natural occurring isotopes. These are hydrogen, deuterium and tritium. The hydrogen and deuterium are the most stable isotopes of hydrogen. The isotope of hydrogen are represented as follows,

Name	symbol	Number of neutron
Hydrogen	H , ${{\text{ }}^{\text{1}}}\text{H }$	0
Deuterium	D , ${{\text{ }}^{2}}\text{H }$	1
Tritium	T , ${{\text{ }}^{3}}\text{H }$	2

The ordinary isotope of the hydrogen with no neutrons is also known as the Protium. Hydrogen atom ${{\text{ }}^{\text{1}}}\text{H }$having an atomic mass equal to $\text{ 1}\text{.007 Da }$ is one of the most abundant isotopes of hydrogen. Out of three isotopes $\text{ 99}\text{.98}{\scriptstyle{}^{0}/{}_{0}}\text{ }$ is comprises of hydrogen or Protium isotope. This is because the nucleus of the Protium isotope contains a single proton. This proton has never seen to undergo the decay and thus ${{\text{ }}^{\text{1}}}\text{H }$ isotope is considered as the stable isotope of hydrogen. Deuterium ${{\text{ }}^{2}}\text{H }$ is also considered as the stable hydrogen isotope.it contains one proton and one neutron. The deuterium exist as the $\text{ 0}\text{.0026}-0.0184{\scriptstyle{}^{0}/{}_{0}}\text{ }$ by the population in the hydrogen sample. Tritium contains one proton and two neutrons. Only a trace amount of tritium exists in the environment. Thus the most abundant isotope of hydrogen is Protium.

Hence, (C) is the correct option.

Note: There are four more isotopes of hydrogen. These are laboratory synthesised isotopes of hydrogen. These are as ${{\text{ }}^{\text{4}}}\text{H }$ , ${{\text{ }}^{5}}\text{H }$, ${{\text{ }}^{6}}\text{H }$and ${{\text{ }}^{7}}\text{H }$. These are highly unstable isotopes of hydrogen. This radioactive isotope further decays into stable isotopes.