Question

define valency and variable valency with two examples​

Answer 1

Explanation:

Valency: The electron present in the outermost

shell is known as valency

eg.

1. Sodium(Na)=(2,8,1) the valency of sodium is 1.
2. Chlorine(Cl)=(2,8,7)the valency of Chlorine is 7.

Answer 2

ʜᴏʟᴀ ᴍᴀᴛᴇ !

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⭐ᴀɴsᴡᴇʀ⭐

Certain elements have more than one valency. They exhibit variable valency. For example, copper, tin, iron and mercury exhibit variable valency. Copper combines with oxygen to form cuprous oxide (Cu2O) and cupric oxide (CuO).