1. Protons: These particles have a positive (+) charge and are found in the nucleus of the atom. The number of protons in an atom determines its atomic number and identifies the element.

2. Neutrons: These particles have no charge (they are neutral) and are also found in the nucleus of the atom. The number of neutrons in an atom can vary, creating different isotopes of the same element.

3. Electrons: These particles have a negative (-) charge and are found orbiting the nucleus in shells or energy levels. The number of electrons in a neutral atom is equal to the number of protons.

These three subatomic particles work together to define the properties of an atom, including its mass, charge, and chemical behavior.