Electrons in atoms can exist at different energy levels. They can move between these levels by gaining or losing energy. Scientists have developed models like the electron cloud model to describe the possible locations of electrons around the atomic nucleus. Electrons are most likely to be found in certain orbital regions within the electron cloud. The arrangement of electrons in an atom's orbitals is referred to as its electron configuration, with the most stable configuration having electrons in the lowest possible energy orbitals.

1. Energy Levels Each electron in an atom has a specific amount of energy. If an atom gains or loses energy, the energy of an electron can change .