Question

what is meant by valency?

Answer 1

The combining capacity of one atom with other is called VALENCY e.g. calcium chloride: calcium combines with two atoms of chlorine so its valency is 2.

Valence is typically, the number of electrons needed to fill the outermost shell of an atom. Because exceptions exist, the more general definition of valence is the number of electrons with which a given atom generally bonds or number of bonds an atom forms. (Think iron, which may have a valence of 2 or a valence of 3.)

Answer 2

Basically all atoms try to have their outermost shell filled to full capacity with electrons. When this is so, the atoms of that element are stable and do not combine with other elements.

For eg . For Helium, the capacity of the outermost shell is 2 and it has two electrons. Thus its outermost shell is filled to capacity and so helium does not react with other substances. Similarly, for Neon, the capacity of outermost shell is 8 and it has eight electrons in it. So here alos the outermost shell is filled completely and so Neon is an inert gas too.

Answer 3

Now if we consider Hydrogen atom, its outermost shell has a maximum capacity of two electrons but has got only one electron. So, if it can get one more electron, its outermost shell will be full and it will become stable.

On the other hand, the outermost shell of oxygen atom has a maximum capacity of eight electrons but has only 6 electrons. If it can get two electrons more, it can fill its outermost shell to full capacity and become stable.

So when two hydrogen atoms and one oxygen atom come together, each hydrogen atom shares its electron with the oxygen atom and so its outermost shell has eight electrons and it becomes stable. Similarly, at the same time, oxygen shares one electron each with each of the two hydrogen atoms and they also become stable. We can imagine that these "shared" electrons are continuously shifting between the two atoms at high speed so that both have them.....

So here hydrogen's valency is 1 and oxygen's valency is 2.

Hope this helps you........

Answer 4

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