Question

Isotopes of an element have always the same number of protons.

• A. True
• B. False

Answer 1

The correct option is A True

Isotopes:

• Isotopes of an element contain an equal number of protons and different numbers of neutrons i.e. they have the same atomic numbers but different mass numbers.
• The chemical properties of an element depend upon the number of protons. Thus, isotopes of the same element have similar chemical properties.
• The physical properties of an element depend upon the mass of the atom i.e. mass number. Thus, isotopes of the same element have different physical properties.

Example: Isotopes of Carbon $\mathbf{\left(}\mathbf{C}\mathbf{\right)}$:

Carbon has three isotopes: $\mathrm{C}-12$, $\mathrm{C}-13$ and $\mathrm{C}-14$.

$\mathrm{C}-12$:

1. It contains $6$ protons and $6$ neutrons.
2. It is represented as ${}_6{}^{12}\mathrm{C}$.

$\mathrm{C}-13$:

1. It contains $6$ protons and $7$ neutrons.
2. It is represented as ${}_6{}^{13}\mathrm{C}$.

$\mathrm{C}-14$:

1. It contains $6$ protons and $8$ neutrons.
2. It is represented as ${}_6{}^{14}\mathrm{C}$.

In all the three isotopes of carbon, the number of protons is the same i.e. $6$. Thus, all the isotopes of an element have always the same number of protons.

Hence, the given statement is true.