13 July 2020- Surprise Topic No.1

A covalent bond forms when two non-metal atoms share a pair of electrons. The electrons involved are in the outer shells of the atoms. An atom that shares one or more of its electrons will complete its outer shell.

Covalent bonds are strong – a lot of energy is needed to break them. Substances with covalent bonds often form molecules with low melting and boiling points, such as hydrogen and water. These substances have strong covalent bonds within the molecules (between the atoms), but weak intermolecular forces between the molecules. This means that only a small amount of heat energy is required to separate the molecules from each other.

Both nuclei are strongly attracted to the shared pair of electrons in the covalent bond, so covalent bonds are very strong and require a lot of energy to break.

A covalent bond forms when two atoms attract the same pair of electrons, which is said to be shared. A covalent bond affects only two atoms, but most atoms can form more than one covalent bond at a time. The compound hydrogen fluoride consists of molecules in which one atom of hydrogen and one atom of fluorine are held together by a covalent bond. Atoms of oxygen or sulfur, however, form two covalent bonds in many of their compounds. Atoms of nitrogen or phosphorus form three or five. Two atoms can share two or three pairs of electrons, forming double or triple covalent bonds.