The force that holds atoms together in compounds is called the chemical bond. Chemical bonds are formed when atoms share or transfer electrons in order to achieve a more stable electron configuration. There are three main types of chemical bonds: covalent bonds, ionic bonds, and metallic bonds.

* Covalent bonds are formed when two or more atoms share one or more pairs of electrons. This creates a strong attraction between the atoms, as they share a mutual interest in the electrons. Covalent bonds are the strongest type of chemical bond.

* Ionic bonds are formed when one or more electrons are transferred from one atom to another. This creates a positive and negatively charged ion, which are attracted to each other. Ionic bonds are not as strong as covalent bonds, but they are still very strong.

* Metallic bonds are formed when the atoms in a metal share a sea of electrons. This creates a strong attraction between the atoms, as they are all attracted to the same pool of electrons. Metallic bonds are not as strong as covalent or ionic bonds, but they are still strong enough to hold metals together.

The type of chemical bond that forms between two atoms depends on the electronegativity of the atoms. Electronegativity is a measure of an atom's ability to attract electrons. The greater the difference in electronegativity between two atoms, the more likely it is that an ionic bond will form. If the electronegativity difference is small, a covalent bond will likely form.