Chemical bonding involves different ways atoms join together to form compounds through the movement or sharing of electrons.
Ionic compounds form when electrons completely transfer between atoms, typically from metals to non-metals. During electron transfer, one atom loses electrons while another gains them, creating oppositely charged ions that attract each other through electrostatic forces. For example, in potassium sulfide, potassium atoms each lose one electron while sulfur gains two electrons, forming K+ and S2- ions that combine in a 2:1 ratio to make K2S. The transfer of electrons creates an ionic bond, which is characterized by the complete movement of electrons from one atom to another.
In contrast, covalent bonds form when atoms share electrons rather than transferring them completely. When electrons are shared between atoms, they form molecular compounds like hydrogen sulfide (H2S). The H2S Lewis structure shows two hydrogen atoms each sharing one electron with a central sulfur atom, while sulfur contributes its electrons to achieve a stable electron configuration. This sharing creates a bent molecular geometry due to the presence of lone electron pairs on the sulfur atom, making H2S a polar molecule. Similar covalent bonding occurs in reactions of alkenes, such as when ethene reacts with bromine. The reaction profile shows an energy diagram illustrating how the π bond in ethene breaks and new bonds form with bromine atoms. Understanding these bonding concepts is crucial for predicting molecular properties and chemical reactivity in both organic and inorganic compounds.
