Home UPPSC Prelims 2025 Mock Test Series MCQs

Question

What is the atomic number of an element?

  1. The number of neutrons in the nucleus
  2. The number of protons in the nucleus
  3. The number of electrons in the outermost shell
  4. The total number of protons and neutrons in the nucleus

Answer:

Option B: The number of protons in the nucleus

Detailed Solution:

The correct answer is “The number of protons in the nucleus”.

The atomic number of an element is defined as the number of protons in the nucleus of an atom of that element.