1. The results of alpha particle scattering test show that most alpha particles do not deflect; A few α particles deflected at a larger angle; A few alpha particles deflect at a large angle (even bounce back)
2. Nuclear size: 10-15~10-14m, atomic radius: about 10-10m (atomic nuclear structure)
3. Emission and absorption of photons: when the atom undergoes a steady state transition, it needs to radiate (or absorb) photons of a certain frequency: h ν=E initial - E final {energy level transition}
4. Composition of atomic nucleus: proton and neutron (collectively referred to as nucleon), {A=mass number=proton number+neutron number, Z=charge number=proton number=extranuclear electron number=atomic number
5. Natural radiation phenomena: alpha ray (alpha particle is helium atomic nucleus), beta ray (high-speed electron flow), gamma ray (electromagnetic wave with extremely short wavelength), alpha decay and beta decay, half-life (more than half of the atomic nuclei have decayed for the time). Gamma ray is produced with alpha ray and beta ray
6. Einstein's mass energy equation: E=mc2 {E: energy (J), m: mass (Kg), c: speed of light in vacuum
7. Calculation of nuclear energy Δ E=Δ mc2 {When the unit of Δ m is kg, the unit of Δ E is J; When Δ m is in atomic mass unit u, the calculated Δ E unit is uc2; 1uc2=931.5MeV}