Counting Atoms

An atom is the smallest unit of matter that retains the properties of an element.

A chemical formula is a way of expressing the number and type of atoms in a substance using symbols and numbers.

A subscript indicates the number of atoms of the element that are present in a molecule.

A coefficient indicates the number of molecules or moles of a substance in a chemical reaction.

There are 3 atoms in H2O (2 Hydrogen and 1 Oxygen).

Add the number of atoms of each element, considering their subscripts.

There are 24 atoms in C6H12O6 (6 Carbon, 12 Hydrogen, 6 Oxygen).

There are 2 atoms of Iron in Fe2O3.

Parentheses indicate that the atoms inside them are grouped together and can be multiplied by a subscript outside the parentheses.

There is 1 atom of Calcium in CaCl2.