In this monograph, group-theoretical approaches are used to build a system of hadrons and qualitatively describe the properties of chemical compounds. This serves as a complement to numerically and approximately solve the many-electron Schrödinger equation, in order to understand the behavior of chemical elements. Besides general theory, specific results are compared with experimentally measured chemical properties.

**Content:
** Symmetries of a quantum system
Observables of a quantum system
Lie groups and Lie algebras
The principles of particle classification
The symmetry group of chemical elements
Classification and chemical properties of elements
Appendix A. Fock's energy spectrum of the hydrogen atom
Appendix B. Representations of some groups

Autorentext

Abram Fet, Russian Academy of Science, Russia.