Predict the number of unpaired electrons for each of the following.
(c) Mn3+
(d) Cr2+

Key Concepts

Electron Configuration

Electron configuration describes the distribution of electrons in an atom's orbitals. For transition metals, this involves filling the 3d and 4s orbitals according to the Aufbau principle, Hund's rule, and the Pauli exclusion principle. Understanding the electron configuration of an element is crucial for predicting its chemical properties, including the number of unpaired electrons.

Unpaired Electrons

Unpaired electrons are electrons that occupy an orbital alone rather than in pairs. The presence of unpaired electrons in an atom contributes to its magnetic properties and reactivity. In transition metals, the number of unpaired electrons can be determined by examining the electron configuration and identifying how many electrons are in the d orbitals without a partner.

Oxidation States

Oxidation states indicate the degree of oxidation of an atom in a compound, reflecting the number of electrons lost or gained. For transition metals, oxidation states can affect the electron configuration significantly. For example, Mn in Mn3+ has lost three electrons, which alters its electron configuration and the number of unpaired electrons compared to its neutral state.