What type of bond holds atoms together in a molecule?

A covalent bond is the type of bond that holds atoms together in a molecule. This occurs when two or more atoms share pairs of electrons, allowing them to achieve a more stable electron configuration. By sharing electrons, the atoms effectively hold onto each other due to the electrostatic attraction between the positively charged nucleus of one atom and the negatively charged electrons that are shared between them.

Covalent bonds are prevalent in organic compounds as well as in many inorganic substances, providing the structural backbone for most molecules in living organisms. The strength of a covalent bond typically allows molecules to maintain their integrity under various conditions, which is essential for the stability and functioning of biological systems.

The other types of bonds listed serve different purposes. Ionic bonds involve the transfer of electrons from one atom to another, leading to the formation of charged ions that attract each other; metallic bonds consist of a 'sea of electrons' shared among a lattice of metal atoms, giving metals their characteristic properties; hydrogen bonds are weaker interactions that occur primarily between molecules, especially in water and biological macromolecules like proteins and DNA.