Question

Which of the following symbols represents the atomic number of an element ?

• A. $\mathrm{Z}$
• B. $\mathrm{p}$
• C. $\mathrm{e}$
• D. $\mathrm{A}$

Answer 1

The correct option is A

$\mathrm{Z}$

The explanation for the correct option

Option A

• The total number of protons present in the nucleus of an atom is called the atomic number.
• It has the symbol “$\mathrm{Z}$”.
• All the isotopes have the same atomic number.
• All the isobars have different atomic numbers.

The explanation for the incorrect answer

Option B

• Every atom is composed of a positively charged subatomic particle called protons.
• Protons are represented by the letter “$\mathrm{p}$”.
• Protons are present inside the nucleus of an atom.
• The number of protons in an atom equals to its atomic number ($\mathrm{Z}$).

Option C

• Every atom is composed of a negatively charged subatomic particle called electrons.
• Electrons are represented by the letter “$\mathrm{e}$”.
• Electrons are revolving around the nucleus in a definite circular path called shells or orbit.
• For a neutral atom, the number of electrons equals to the number of protons.

Option D

• The total number of protons and neutrons present in the nucleus of an atom is called the mass number.
• It has the symbol “$\mathrm{A}$”

Thus, option A is the correct answer. $\mathrm{Z}$ represents the atomic number of an element.