Question

What does the statement-"The atomic number of an atom of the same element never changes" mean?

Answer 1

Atomic number:

1. The atomic number for an element is denoted by $\mathrm{Z}$.
2. The atomic number of an element is equal to the number of protons present in the nucleus of an atom.
3. The number of protons for the same element never changes. It always remains the same.
4. Therefore, the atomic number for the same element is unique and never changes.

Example:

1. A neutral Oxygen $\mathbf{\left(}\mathbf{O}\mathbf{\right)}$ atom contains $8$ protons.
2. Thus, the atomic number of Oxygen is $8$.