Question

what do mean by atomic number and mass number ?​

Answer 1

Answer:

Atomic No. The total number of protons in the nucleus of an atom gives us the atomic number of that atom.

Explanation:

Atomic mass The number of protons and neutrons combined to give us the mass number of an atom.

Answer 2

Answer:

Atomic number :is the number of a chemical element in the periodic system, whereby the elements are arranged in order of increasing number of protons in the nucleus.

Atomic mass number :is the sum of the numbers of protons and neutrons present in the nucleus of an atom.