Question

The elements which exhibit more than one valency are said to exhibit ________ valency.

Answer 1

Valency:

• The combining capacity of an atom is known as its valency.
• The number of electrons accepted or donated by an atom of an element to get eight electrons in their outermost shell is called valency.

Variable valency:

• Some atoms of elements can donate electrons from their inner orbits in addition to their outermost orbital, then it is called variable valency.
• Therefore, the elements which exhibit more than one valency are said to exhibit variable valency.
• The suffix “ous” is used to indicate the lower valency and the suffix “ic” to indicate the higher valency.
• For example Oxides of Iron $\left(\mathrm{FeO}\right)$= ${\mathrm{Fe}}^{2+}$ has valency 2, and ${\mathrm{Fe}}_2{\mathrm{O}}_3$ = ${\mathrm{Fe}}^{3+}$has valency 3.

Hence, the elements that exhibit more than one valency are said to exhibit variable valency.