Question

Atomic number of nitrogen is 7. The number of protons in nitrogen is equal to ________.
A) 14
B) 7
C) 21
D) 15

Answer 1

Hint: The atomic number is equal to the number of electrons. In general, the number of the electrons in a neutral atom is equal to the number of protons of that atom.

Complete step by step answer:
In the modern periodic table nitrogen is present in period 2 and group 15.
The atomic number of nitrogen is given in the question which is 7.
This means seven electrons are filled in the orbitals of electrons.
Let us try to write the electronic configuration of nitrogen:
$$N_7=1s^{2}2s^{2}2p^3$$
Now, since we know that nitrogen given in the question is neutral, we know that:
Atomic number = Number of electrons = Number of protons
So we can say that the number of protons in nitrogen is equal to 7.

Therefore, we can conclude that the correct answer to this question is option B.

Additional information:
 Nitrogen is the lightest member of group number 15 of the modern periodic table and is often called the Pnictogens.
The electronegativity of nitrogen is also very high.
We know that the lack of radial nodes in the $$2\text{p}$$ subshell is directly responsible for many of the anomalous properties of the nitrogen.
As nitrogen consists of half-filled of the $$2\text{p}$$ orbitals, it shows many anomalous properties.
We know that the nitrogen may be usefully compared to its horizontal periodic neighbor’s carbon and oxygen as well as its vertical group’s neighbors in the pnictogen column, phosphorus, arsenic, antimony, and bismuth.

Note:
We can get confused between the atomic number and atomic mass number. As the atomic number is equal to the number of the proton on the other side, atomic mass number is equal to the number of protons and number of neutrons combined.