Question

Li has 1 electron in its outer shell, Cl has 7 electrons in its outer shell. Choose the correct option:

• A. Li and Cl have valency +1 and -7 respectively
• B. Li and Cl have valency +1 and -1 respectively
• C. Li and Cl have valency +1 and -6 respectively
• D. Li and Cl have valency 0 and -1 respectively

Answer 1

The correct option is B Li and Cl have valency +1 and -1 respectively

Valency of an atom is the number of electrons it is willing to give up or the number of electrons it is willing to accept in order to achieve electronic configuration of nearest stable noble gas.. Here if Lithium gives up one electron, it achieves the configuration of Helium which is stable. So the valency of Lithium is 1.
Similarly, Chlorine accepts 1 electron to achieve the configuration of Argon. So the valency of chlorine is 1.