You probably know by now (through your studies of chemistry) that electrons are the “magic” behind chemical reactions.
If you’re taking a chemistry class or even a general science class, chances are pretty good that you have a copy of the Periodic Table of Elements.
If I put a small piece of sodium metal in some water, a reaction occurs. The sodium fizzes and races around and there is an orange flame.
The chemical concept of a “mole” is very important to be able to perform calculations in chemistry. Remember from your class that an atom’ atomic weight refers to the number of grams in one “mole” of that material.