Question

What is meant by zero valency and variable valency? Give two examples of each.​

Answer 1

Answer:

Some elements possess more than one valence. Such elements are said to possess variable valency.

For example, iron has two electrons in its outermost shell (valence shell). On donating these electrons, its valency becomes 2. However, under specific experimental conditions, it can lose another electron from the shell next to valence shell. In such a case, the ion formed has 3 electropositive valencies.

Answer 2

Answer:

࿓⇒ Zero valency :

The valence or valency of an element is a measure of its combining power with other atoms when it forms chemical compounds or molecules. Noble gas family has zero valency. Helium, Neon, Radon and Argon have zero valency because they have their outer shell completely filled and are chemically inert gas.

Hence, we can say that Helium, Neon and Argon have zero valency.

➔ Variable valency :

In transition elements, an atom loses electrons from the shell next to the valence shell (penultimate shell). In such a situation the element exhibits more than one valency (variable valency).

For example, copper, tin, iron and mercu-

ry.

꧁༺Jαcƙッᶦᵈᵒᶫ༻꧂