The number of protons in an atom of an element is equal to its-

Correct option is C

The correct answer is (c) Atomic number.
· The atomic number of an element is the number of protons in the nucleus of an atom. It is a unique identifier for each element and determines the chemical properties of the element.
· The atomic number also equals the number of electrons in a neutral atom, ensuring the atom remains electrically neutral.
· For example, hydrogen has an atomic number of 1, meaning it has 1 proton, and carbon has an atomic number of 6, meaning it has 6 protons.
· The atomic number is critical in classifying elements in the periodic table, as it defines the element's identity.
· Isotopes of an element have the same atomic number but different numbers of neutrons, meaning they have different atomic masses.
Additional Knowledge:
· Electron affinity: Refers to the energy change when an atom gains an electron, not related to the number of protons.
· Atomic weight: Refers to the average mass of an atom, which includes both protons and neutrons.
· Equivalent weight: A concept in chemistry that relates to the amount of an element that reacts with a fixed quantity of another substance, not directly tied to the number of protons.