Final answer:
A covalent bond is an attraction between two atoms sharing a pair of valence electrons, typically between nonmetals. Nonmetals form covalent bonds to attain an octet in the valence shell, with the number of bonds each can form relying on their valence electrons. This bond is central to forming molecules like water (H2O) and ammonia (NH3).
Step-by-step explanation:
What is a Covalent Bond?
A covalent bond is the force of attraction that holds together two atoms that share a pair of valence electrons. This form of chemical bond is prevalent between nonmetal atoms, which have similar electronegativities and a tendency to fill their valence electron shells by sharing electrons rather than transferring them.
Elements Forming Covalent Bonds
Typically, covalent bonds form between nonmetal elements. For example, in a molecule of water, hydrogen and oxygen share electrons to form covalent bonds. You can determine how many covalent bonds an element can form by looking at its valence electrons: elements try to reach an octet configuration, which means having eight valence electrons, mirroring the electron configuration of noble gases.
Nitrogen, which is a diatomic element with five valence electrons, requires three additional electrons to complete its octet. It tends to form three covalent bonds with other elements like hydrogen, resulting in the formation of ammonia (NH3) where nitrogen shares its valence electrons with three hydrogen atoms.
Representation of a Covalent Compound
A covalent compound is typically represented by a molecular formula showing the types and numbers of atoms involved in the molecule. The shared pairs of electrons that constitute covalent bonds are often depicted as lines between the bonded atoms.