Question

what is variable valency ? example. with a elaborate knowledge but short detention.​

Answer 1

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✒️ SOMETIMES, SAME ELEMENT MAY EXHIBIT ONE VALENCY IN ONE COMPOUND AND ANOTHER VALENCY IN OTHER COMPOUND.

✒️THIS PROPERTY IS TERMED AS VARIABLE VALENCY.

✒️SOME ELEMENTS SHOW VARIABLE VALENCY BECAUSE OF DIFFERENT ELECTRONIC CONFIGURATIONS.

✒️AN ATOM OF AN ELEMENT CAN SOMETIMES LOSE MORE ELECTRONS THAN ARE PRESENT IN VALENCE SHELL i.e. LOSS FROM THE PENULTIMATE SHELL AND HENCE EXHIBIT MORE THAN ONE VALENCY.

✒️SOME OF THE ELEMENTS THAT SHOW VARIABLE VALENCY ARE IRON , COPPER, CHROMIUM ,MANGANESE ,MERCURY ETC...

Answer 2

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The variable valency is an atom is equal to the valence electrons, if it is 4 or less.

The electrons present in the outermost shell of an atom are called valence electrons.

For example : iron combines with oxygen to form ferrous oxide as well as ferric oxide.