Question

Atomic number and mass number are the basic parameters which help us know the number of fundamental particles inside an atom. What does an atomic number of an element refer to?

• A. Number of protons in the atom
• B. Mass of the atom
• C. Number of neutrons in an atom
• D. Number protons and neutrons in an atom.

Answer 1

The correct option is A Number of protons in the atom

The Atomic number refers to the number of protons in an atom. As atoms are always neutral, the number of electrons (negatively charged species) are equal to the number of protons (positively charged species). The mass number is equal to the sum of protons and neutrons in an atom.