When a metal loses an electron, it undergoes a process known as oxidation or ionization. The loss of an electron from a metal atom affects its atomic structure in the following ways:
Formation of a cation: When a metal atom loses one or more electrons, it becomes a positively charged ion known as a cation. The number of protons in the nucleus remains the same, but the loss of negatively charged electrons leads to an imbalance in charge. For example, if a sodium (Na) atom loses one electron, it becomes a sodium cation (Na+) with a positive charge. The positive charge on the cation is equal to the number of electrons lost.
Smaller atomic radius: The loss of an electron reduces the electron cloud surrounding the nucleus. Since electrons contribute to the volume of an atom, the removal of an electron leads to a decrease in atomic radius. This reduction in size is mainly observed in the valence shell from which the electron is lost.
Electronic configuration change: Losing an electron changes the electronic configuration of the atom. The electron configuration determines the arrangement of electrons in different energy levels or electron shells. For example, if a magnesium (Mg) atom loses two electrons, its electronic configuration changes from 2-8-2 to 2-8, resembling the noble gas neon (Ne). Metals tend to lose electrons to achieve a stable electron configuration, often resembling the nearest noble gas configuration.
Increased positive charge: With the loss of one or more electrons, the metal cation carries a positive charge. The positive charge is equal to the number of electrons lost. This positive charge attracts other negatively charged species, such as electrons or anions, due to the electrostatic force.
Overall, when a metal loses an electron, its atomic structure undergoes changes such as the formation of a cation, a smaller atomic radius, a modified electronic configuration, and an increased positive charge. These changes play a crucial role in the chemical properties and reactivity of metals.