Question

Which of the following is an isotope of hydrogen?
A. Deuterium
B. Trinium
C. Promium
D. All of the above

Answer 1

Hint:
We know that there are $3$ isotopes of hydrogen which have different names.

Complete step by step solution
We know that different elements are found in different forms making it a vast area of gathering and organizing information about all of them. For some elements, we have different isotopes as well that can be defined as variants for which: number of protons $\left( {{{\rm{n}}_{\rm{p}}}} \right)$ are equal but not that of neutrons $\left( {{{\rm{n}}_{\rm{n}}}} \right)$
As it is number of protons that gives the atomic number $\left( {\rm{Z}} \right)$ that can be written as follows:
${\rm{Z}} = {{\rm{n}}_{\rm{p}}}$
So, we can say that for isotopes, the value of ${\rm{Z}}$ is the same. However, the mass number $\left( {\rm{A}} \right)$ is given by number of protons as well as that of neutrons and can be written as follows:
${\rm{A}} = {{\rm{n}}_{\rm{p}}} + {{\rm{n}}_{\rm{n}}}$

So, we can say that for isotopes, the value of ${\rm{A}}$ is different.

We can take nitrogen for example, it has mainly two natural isotopes that are: \[_7^{14}{\rm{N \, and }} \, _7^{15}{\rm{N}}\] For both of the isotopes, atomic number is same $\left( {{\rm{Z}} = {\rm{7}}} \right)$ for both of them have equal number of protons $\left( {{{\rm{n}}_{\rm{p}}} = 7} \right)$ but \[_7^{14}{\rm{N}}\] isotope has $\left( {{\rm{A}} = {\rm{14}}} \right)$ and \[_7^{15}{\rm{N}}\] isotope has $\left( {{\rm{A}} = {\rm{15}}} \right)$ as $\left( {{{\rm{n}}_{\rm{n}}} = 7} \right)$ for \[_7^{14}{\rm{N}}\] and $\left( {{{\rm{n}}_{\rm{n}}} = 8} \right)$ for \[_7^{15}{\rm{N}}\].

Now, let’s have a look at the isotopes of hydrogen that are $_1^1{\rm{H}}$, $_1^2{\rm{H}}$ and. As it is evident that all of them have $1$ proton but the number of neutron(s) is $0 ,1{\rm{ \, and \, 2}}$ and are known as protium, deuterium, and tritium respectively.

As we can see that in the given options, only deuterium is the isotope of hydrogen.

Hence, the correct option is A.

Note:
We have to be careful with the spellings of the name as the wrong options also have similar but incorrect names.