How do ions form in metallic and non-metallic elements?

Ions form in metallic elements through loss of electrons, and in non-metallic elements through gain of electrons.

In metallic elements, ions form through a process known as ionisation. This is when an atom loses one or more of its electrons, resulting in a positively charged ion, also known as a cation. This process occurs because metals have a tendency to lose electrons in order to achieve a stable electron configuration. For example, sodium (Na) has one electron in its outermost shell. To achieve a stable electron configuration, it loses this electron to form a sodium ion (Na+).

On the other hand, non-metallic elements form ions by gaining one or more electrons. This results in a negatively charged ion, also known as an anion. Non-metals tend to gain electrons to achieve a stable electron configuration. For instance, chlorine (Cl) has seven electrons in its outermost shell. It needs one more electron to achieve a stable configuration. Therefore, it gains an electron to form a chloride ion (Cl-).

The formation of ions is a fundamental concept in chemistry, as it underpins many chemical reactions. In particular, it is crucial to the formation of ionic compounds, which are formed when a metal and a non-metal react. The metal loses electrons to form a cation, and the non-metal gains these electrons to form an anion. These oppositely charged ions are then attracted to each other, forming an ionic bond. For example, when sodium (Na) reacts with chlorine (Cl), sodium loses an electron to become Na+, and chlorine gains this electron to become Cl-. These ions then attract each other to form the ionic compound sodium chloride (NaCl), which is common table salt.