Question

An atom of an element is represented as ${}_{11}{}^{23}\mathrm{X}$.

What does the numeral 11 indicate?

Answer 1

• The atoms are written in this manner ${}_{\mathrm{Z}}{}^{\mathrm{A}}\mathrm{X}$ where A denotes mass number and Z denotes the atomic number.
• Atomic number(Z)- The total number of protons in the nucleus of an atom gives us the atomic number of that atom.
• Protons are positively charged subatomic particles present in the nucleus of an atom.

Hence, In ${}_{11}{}^{23}\mathrm{X}$ the number 11 indicates its atomic number.