Core Concept

Electron configurations = how electrons are distributed among the energy levels, sublevels, and orbitals of an atom. They provide a structured representation of the arrangement of electrons, which plays a crucial role in determining an atom's chemical properties and behavior.

Aufbau principle, electrons fill the lowest energy levels and sublevels first before occupying higher energy levels. This means that the 1s sublevel is filled before the 2s, which is filled before the 2p, and so on. The order of filling is based on the increasing energy of the sublevels.

Pauli exclusion principle states that no two electrons in an atom can have the same set of quantum numbers. This means that within an orbital, the two electrons must have opposite spins, represented as up and down arrows.

Hund's rule states that within a sublevel, electrons occupy separate orbitals with the same spin before pairing up in the same orbital. This minimizes electron-electron repulsion and promotes stability.

shorthand notation called the noble gas notation. This notation involves using the symbol of a noble gas, such as helium (He), neon (Ne), or argon (Ar), to represent the fully occupied energy levels and sublevels that precede the element of interest. The remaining electrons are then described using the appropriate sublevel designations.

WHY ITS IMPORTANT:

Understanding electron configurations is crucial for predicting an atom's reactivity, bonding behavior, and the formation of ions. It provides insights into an element's valence electrons, which are the outermost electrons involved in chemical bonding and interactions.