The representation of electron shells as circles in atomic models is a simplification used for conceptual understanding and visual clarity. Electron shells are three-dimensional regions around the nucleus where electrons are likely to be found.
In reality, electron shells do not have a precisely defined boundary or shape like a geometric circle or sphere. The shape of an electron orbital, which describes the probability distribution of finding an electron, is more complex and can take various forms such as spheres, dumbbells, or more intricate shapes depending on the energy level and orbital type (s, p, d, f).
The circular depiction of electron shells in atomic models is a visual convention that provides a simplified representation of the electron's distribution in a two-dimensional space. This representation helps convey the idea of discrete energy levels and the increasing distance of electron shells from the nucleus as the energy level increases.
While the circular representation is a useful tool for basic understanding, it is important to recognize that it does not accurately reflect the true three-dimensional nature of electron distribution in atoms. In more advanced models or scientific discussions, more accurate representations, such as electron density plots or mathematical equations, are used to describe the shapes of electron orbitals.