Question

There are _____ isotopes of Hydrogen.
A.0
B.1
C.2
D.3

Answer 1

Isotopes are those species whose mass number is different but atomic number is same. We encounter the isotopes of hydrogen in nuclear reaction and heavy water.

Complete step by step answer:
Let us look at the properties of Hydrogen and its isotopes. Hydrogen is the first element of the periodic table and its symbol is H, the atomic number of hydrogen is 1 and the mass number is also 1. It has one proton and zero neutrons in its nucleus.
The representation of hydrogen will be${\text{H}}_{\text{1}}^{\text{1}}$.
We know that isotopes are those species in which the atomic number of the elements is the same but the mass number varies. Hydrogen is the only element in which the isotopes have different names. In hydrogen, there are three isotopes that are Hydrogen, Deuterium and Tritium, with the atomic symbols H, D and T, respectively.
They are represented as follow:
Hydrogen or Protium ${\text{H}}_{\text{1}}^{\text{1}}$
Deuterium ${\text{D}}_{\text{1}}^{\text{2}}$ or ${\text{H}}_{\text{1}}^{\text{2}}$
Tritium ${\text{T}}_{\text{1}}^{\text{3}}$ or ${\text{H}}_{\text{1}}^3$
The most abundant isotope of hydrogen is Protium. It is more than $99.98\%$ because it has only one proton in its nucleus that is why it is named as Protium. Whereas, Deuterium consists of one proton and one neutron and Tritium consists of one proton and two neutrons.

So, the correct answer is Option D .

Note:
There are two terms which are often confusing that are isotope and isobar. Isotope is what we have discussed above and Isobar is the same atomic mass but different atomic number. Example of isobar is potassium and calcium which have the same atomic mass but different atomic numbers.