Question

Atomic weights of carbon, nitrogen and oxygen are $12$, $14$ and $16$ respectively. An atom of atomic weight $14$ and nuclear charge $+ 6$ is an isotope of:
A.Oxygen
B.Carbon
C.Nitrogen
D.None of these

Answer 1

The nucleus of an atom consists of neutrons and protons. The mass of the atom is considered equal to the mass of the nucleus as the mass of electrons is negligible in comparison to the mass of protons.

Complete step by step answer:
We know that protons are positively charged while neutrons carry no charge. Thus the charge in the nucleus is solely due to the protons. As a result, we can say that nuclear charge gives us the atomic number of the atom. In the given question, the nuclear charge of the given atom is $+ 6$, which gives us the atomic number also as$6$. The atomic weight of the atom is given to be $14$ which is the same as that of nitrogen.
But, we know that an atom is defined by its atomic number. Thus the given atom is an isotope of carbon.

The correct option is B.

Note:
An Atom of each element contains a fixed number of protons. Rather, we can say that the number of protons determines the atom we are considering. We are familiar with the fact that the number of protons in an atom is called the atomic number of the atom. Unlike the number of protons, the number of neutrons for a certain element can vary. Atoms of the same element that differ only in the number of neutrons in their nucleus are called isotopes. Together, the number of protons and the number of neutrons determine the atomic mass of the element.