Atomic Number:

* Identifies the element: Each element has a unique atomic number. It's like the element's fingerprint.

* Indicates the number of protons: The atomic number tells you exactly how many protons are in the nucleus of an atom. Since the number of protons defines the element, the atomic number is crucial.

Atomic Mass:

* Represents the average mass of the atom: The atomic mass is a weighted average of the masses of all the isotopes of an element. Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.

* Closely related to the number of protons and neutrons: The atomic mass is primarily determined by the number of protons and neutrons in the nucleus. Since electrons have a very small mass, they don't significantly contribute to the overall atomic mass.

In summary:

* Atomic number is like an element's ID card, telling you what element it is.

* Atomic mass gives you an idea of the overall weight of the atom, taking into account the different isotopes of the element.