Question

The following table lists the mass number and the atomic number of the five elements:

A, B, C, D, and E

Element	Mass number	Atomic number
A	3	1
B	7	3
C	35	17
D	40	18
E	37	17

How many protons are there in an atom of B?

Answer 1

Protons:

1. The positively charged particles present at the center of the nucleus is known as proton.
2. Number of protons in an atom is equal to the atomic number of that atom.
3. Protons are situated in the nucleus along with neutron.

According to the question,

Atomic number of B is 3.

As we know,

$\mathrm{Number}\mathrm{of}\mathrm{protons}=\mathrm{Atomic}\mathrm{number}\mathrm{of}\mathrm{the}\mathrm{element}=3$

Hence, number of protons in element B is three.