Write the electron configurations of Co, Co^2+, and Co^3+.

Electron configuration describes the distribution of electrons in an atom's orbitals. It follows the Aufbau principle, which states that electrons fill the lowest energy orbitals first, and is represented using a notation that indicates the energy levels and sublevels occupied by electrons. Understanding this concept is crucial for determining how many electrons are present in an atom and how they are arranged.

Transition metals, such as cobalt (Co), are elements found in the d-block of the periodic table. They are characterized by their ability to form variable oxidation states and complex ions due to the involvement of d electrons in bonding. This property is essential for understanding how cobalt can lose electrons to form Co^2+ and Co^3+ ions, affecting its electron configuration.

Oxidation states indicate the degree of oxidation of an atom in a compound, reflecting the number of electrons lost or gained. For cobalt, the oxidation states of +2 and +3 correspond to the loss of two and three electrons, respectively. This change in oxidation state alters the electron configuration, as fewer electrons will occupy the orbitals, which is key to writing the configurations for Co, Co^2+, and Co^3+.