Explain the fundamental differences between protons, neutrons, and electrons in terms of their charge, mass, and location within an atom.

Protons have a positive charge (+1), a mass of approximately 1 atomic mass unit (amu), and are located in the nucleus. Neutrons have no charge (neutral), a mass of approximately 1 amu, and are also located in the nucleus. Electrons have a negative charge (-1), a very small mass (approximately 1/1836 amu), and orbit the nucleus in electron shells.