Elements are pure substances that cannot be broken down further by chemical means, while compounds are formed when two or more elements combine chemically. Elements get their names from various sources like the element's color, the scientist who discovered it, or its planet of origin. Symbols are used to represent elements, often taking the first letter of the element's English name. Atoms are the smallest particles that make up elements and exhibit the properties of that element, while molecules are the smallest particles that can independently exist and may contain multiple atoms. Chemical formulas are used to show the atoms that make up molecules or compounds. Balanced chemical equations ensure the number of atoms of each element are equal on both sides of the reaction.