Physics of Atoms and Ions
General concepts of physics of atoms are considered. A general atom scheme takes the Coulomb interaction of electrons with the nucleus and between them as the strongest interaction which together with the Pauli principle for electrons leads to the shell atom structure. More weak interactions include an exchange interaction of electrons and spin-orbit interaction which determine the scheme of momentum coupling in the atom and its quantum numbers. The detailed analysis is fulfilled for properties of the hydrogen and helium atoms located in the ground and excited states. The analysis of lowest excited states of inert gas atoms is a demonstration of momentum coupling in atoms. Information is collected for spectral parameters of atoms with s and p valence electrons in the ground state.