Physics - Modern Physics - Atomic Structure - Structure of the atom - Inside the Atom

A 5-step lesson. Step 1: 'Atoms have 3 particles: Protons (positive, mass ≈ 1u, in nucleus), Neutrons (neutral, mass ≈ 1u, in nucleus), Electrons (negative, mass ≈ 1/1836 u, in shells orbiting nucleus). The nucleus is tiny but contains 99.97% of the mass!' Step 2: 'Atomic number (Z) = number of prot