Define valency.

Define co-valency.

In which reaction there is a change in valency

(a) Define a ligand . (b) Discuss the magnetic behaviour , nature and geometry of (NiCl_(4))^(2-) ion on the basis of valence bond theory (VBT)

An element has atomic number 15. What will be the valency/valencies shown by it?

Does the number of valence electron (s) in an atom determine the valency of the element concerned ?

Write valency of element E.

Variable valency is generally shown by-