Question

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

Answer 1

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.