Which elements achieve greater chemical stability by having two half-full sublevels?

Answer 1

Elements that achieve greater chemical stability by having two half-full sublevels are typically found in the transition metals, particularly those in the d-block. For example, chromium (Cr) and copper (Cu) exhibit this stability. In these cases, electrons are redistributed to create half-filled (d^5) or fully-filled (d^10) configurations, which provide lower energy states and enhanced stability due to decreased electron-electron repulsion and increased symmetry. This phenomenon is a key factor in their chemical behavior and reactivity.