Chlorine is a halogen element that belongs to Group 17 (VIIA) of the periodic table. It has seven electrons in its valence shell, which means that it needs to gain one electron to achieve a stable configuration. This is why chlorine atoms tend to form covalent bonds with other atoms, in which they share electrons to complete their valence shells.

In chlorine molecules, each chlorine atom shares one electron with another chlorine atom, resulting in a single covalent bond. This covalent bond is formed by the overlap of the atomic orbitals of the two chlorine atoms, which results in the sharing of an electron pair. The covalent bond in chlorine molecules is quite strong, which is why chlorine is a stable diatomic gas at room temperature.

The covalent bonding in chlorine can also be represented using a Lewis structure. In a Lewis structure, the valence electrons of the atoms are represented by dots placed around the atomic symbols. For a chlorine molecule, the Lewis structure is as follows:

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Cl - Cl

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This Lewis structure shows that each chlorine atom has seven valence electrons, with one electron being shared between the two chlorine atoms to form a covalent bond.