In metals, positive ions are surrounded by a cloud of delocalized electrons that can move independently. The discussion explores why these electrons leave their atoms to form ions. Sufficient energy can remove electrons from metal atoms, with the energy required decreasing as the period number increases and being directly proportional to electronegativity. Electrochemical reactions can also lead to ion formation, as seen when elemental potassium reduces mercury(II) ions. It's important to note that when an electron departs from a metal atom, another electron from a neighboring atom moves in to maintain electrical neutrality, facilitating electrical conduction. The ability of certain elements to allow electron mobility, distinguishing conductors from insulators, is explained through quantum mechanics, particularly the "layer principle," which highlights the minimal energy gap in conductors compared to the significant gap in insulators. Molecular orbital theory further elucidates these differences in electron behavior.
