How are covalent bonds formed?

Covalent bonds are formed by sharing electrons between two non-metals, which is the fundamental characteristic of this type of bond. In covalent bonding, atoms have similar electronegativities and thus do not significantly transfer electrons as seen in ionic bonding. Instead, they overlap their outer electron shells, allowing each atom to achieve a stable electron configuration. This sharing of electrons allows both atoms to count the shared electrons toward their own stability, often leading to the formation of molecules.

For instance, in a water molecule (H2O), each hydrogen atom shares one electron with the oxygen atom, resulting in a stable arrangement where the outer shells of all participating atons are filled according to the octet rule. This shared electron arrangement is what makes the bond covalent rather than ionic or metallic. Understanding this distinction is crucial in recognizing how different types of bonds operate within compounds.