Question

Number of isotopes of carbon is
A. $3$
B. $4$
C. $5$
D. $6$

Answer 1

The relative percentage of abundance of each isotope is used to compute the average atomic mass of any element that has more than one isotope. The isotope with the greatest abundance is expected to have the greatest impact on average atomic mass.

Complete answer:
Carbon is the first element in the current periodic table's fourteenth group, and it is tetravalent because it has four electrons in its outermost shell.
The three types of carbon elements have the same number of protons in their nuclei (as well as the same number of electrons in neutral states), but varying numbers of neutrons. Isotopes are elemental forms that have the same chemical symbol and atomic numbers but different mass numbers.
Carbon $12$ , Carbon $13$ and Carbon $14$ are the three isotopes of carbon. In nature, these isotopes are not present in equal amounts. Some of these isotopes are abundant in nature, whereas others are less stable and only found in trace amounts.
The average atomic mass is calculated by multiplying the relative abundance by the atomic mass number of each isotope. As a result, the average atomic mass value is the most similar to the mass of isotopes with the greatest relative abundance in nature.
Carbon isotopes have an average atomic mass value of $12.011$ , which is closest to Carbon $12$ , and hence Carbon $12$ is the most abundant isotope.
Hence, the correct option is A. $3$

Note:
Because there are more neutrons in the nucleus than protons, the atom becomes exceedingly unstable, and heavier nuclei are always less abundant and likely to dissolve. As a result, isotopes with lower atomic masses are commonly utilised to represent chemical species since they are more prevalent.