・1240: The electrons of an atom are in atomic orbitals
　Why do electrons enter atomic orbitals? Topics: standing waves, wave functions, atomic orbitals, stationary state, potential energy, kinetic energy, virial theorem

・1250: Discontinuity in the energy values of atoms
　Why the electron energy of an atom is discontinuous. Topics: quantization, standing waves, wave interference, half wavelength, quantum numbers, atomic orbitals

・1260: Types of atomic orbitals
　Explains the types of atomic orbitals and their origins. Topics: Cartesian coordinates, polar coordinates, types of quantum numbers that represent dimensions, principal quantum number, azimuthal quantum number, magnetic quantum number

・1270: Types and symbols of atomic orbitals
　Explanation of notations. Topics: Principal quantum number, azimuthal quantum number, magnetic quantum number, Cartesian coordinates

・1280: Shape of atomic orbitals
　Reasons for the various shapes of atomic orbitals. Topics: Phase change of wave function, quantum numbers and nodes of wave function, functional form of atomic orbitals, principal quantum number, azimuthal quantum number, magnetic quantum number

・1290: Distribution of electrons on atoms and shape of atomic orbitals
　The shape of atomic orbitals and the shape of electron distribution are different topics: distribution function, square of wave function, isoradial distribution

・1300: Diagram of the energy levels of atomic orbitals
　The energy levels of the hydrogen atom's atomic orbitals are determined only by the principal quantum number. Topics: Energy levels of the hydrogen atom's atomic orbitals, Energy levels of the atomic orbitals of multi-electron atoms

・1310：In the energy levels of multi-electron atoms, the azimuthal and magnetic quantum numbers are separated
　The energy of atomic orbitals of multi-electron atoms varies depending on the azimuthal quantum number. Explain the reason for this. Topics: Orbitals, repulsion with inner shell s orbital electrons, relationship between force and energy

・1320: Rules for entering atomic orbitals of multi-electron atoms
　This is extremely important as the foundation of organic chemistry. Topics: Electron spin, alpha spin, beta spin, Pauli principle, Hund's rule, Bose particles, fermions, spin quantum number, total spin quantum number, magnetic moment, degeneracy, spin multiplicity, electron configuration

・1330: Transition elements　　　　　　　　　　　　　　　　Periodic Table
　A brief explanation of the origin of the transition elements. <Topics: Main group elements, Transition elements, Lanthanides (Lanthanide family), Actinides (Actinide family), Spin-orbit interaction