EVERYDAY SCIENCE

Detailed explanation-1: -The valencies of aluminium and chlorine in the compound AlCl3 respectively are 3, 1. Valency is the combining power of an element.

Detailed explanation-2: -Chlorine has a valency of 1. Chlorine has an atomic number of 17. Chlorine’s electrical configuration is Ne3s23p5, which can also be represented as 2, 8, 7. This demonstrates that chlorine’s outermost shell has seven valence electrons.

Detailed explanation-3: -Valency of chlorine is taken as 1 because it gains one electron from other atoms to attain stability and form a molecule.

Detailed explanation-4: -Due to its electronegativity, chlorine gains an electron rather than losing seven of its electrons (which is a difficult process for even electropositive elements. Therefore chlorine has its valency equal to one and not seven.

Detailed explanation-5: -Since sodium has only one electron in the outermost shell which takes part in the bonding its valency is +1 . Chlorine atoms can accept the electron in 3p orbital to attain the nearest noble gas configuration of Ar . Chlorine has 7 valence electrons. It requires one more electron to complete its octet.