1. Wave-particle duality: This is the cornerstone of quantum mechanics. Electrons can act like both waves and particles, depending on the situation.

* Wave-like behavior: Electrons can diffract and interfere, like light waves. This is observed in phenomena like the double-slit experiment.

* Particle-like behavior: Electrons can be localized and interact with other particles as discrete entities. This is evident in their behavior in circuits and atomic structure.

2. Quantization: Electrons can only exist in specific energy levels within an atom or molecule. This means their energy is quantized, meaning it can only take on discrete values.

* Energy levels: Electrons jump between these energy levels by absorbing or emitting photons of specific energies. This is the basis for atomic spectroscopy.

These two behaviors are essential to understanding the behavior of electrons in various contexts, from the microscopic world of atoms to the macroscopic world of electronics.