Question

What is variable valency ? Name two elements having variable valency and state their valencies.

Answer 1

Variable valency: Some elements exhibit more than one valency. They are said to have variable
valency, e.g. Iron, copper, tin, lead.
Iron Fe $F{e}^{2+}$ or $F{e}^{3+}$
Copper cu $C{u}^{+}$ or $C{u}^{2+}$