What are two types of bonds?

The two main types of chemical bonds are ionic bonds (electron transfer between metals and non-metals) and covalent bonds (electron sharing, usually between non-metals).

Chemical bonding explains how atoms join to make molecules and compounds. In an ionic bond, one atom loses electrons to become a positively charged ion (cation) and another gains electrons to become a negatively charged ion (anion). The electrostatic attraction between opposite charges holds the crystal together. This commonly occurs between metals (like sodium) and non-metals (like chlorine), producing salts such as NaCl.

In a covalent bond, atoms share one or more pairs of electrons to fill their outer shells. This usually happens between non-metals, as in H₂, O₂, H₂O, CO₂, and organic molecules. Covalent bonds can be single, double, or triple depending on how many electron pairs are shared. If sharing is equal, the bond is non-polar (e.g., Cl₂); if sharing is unequal due to different electronegativities, it becomes polar (e.g., the O–H bonds in water).

While ionic and covalent are the core types, you should also know about metallic bonds (a “sea” of delocalized electrons among metal cations, giving metals their conductivity and malleability) and hydrogen bonds (strong dipole attractions important in water and DNA). But for most school exams, naming and comparing ionic vs covalent bonds with examples is enough.