No, the valency of chlorine (Cl) is not 4. The valency of an element refers to the number of electrons it needs to gain or lose to achieve a stable electron configuration. Chlorine is a halogen and belongs to Group 17 of the periodic table, also known as the halogens or Group 7A.
Chlorine has seven valence electrons, as it is located in Group 17, and its electronic configuration is 1s² 2s² 2p⁶ 3s² 3p⁵. To achieve a stable electron configuration, chlorine tends to gain one electron to fill its outermost electron shell and attain a noble gas configuration similar to that of argon.
Therefore, chlorine typically has a valency of 1, meaning it tends to gain one electron to achieve a stable configuration with eight valence electrons. It forms an anion with a charge of -1, represented as Cl^-.