Question

The valency of both potassium and chlorine is 1 why ??

Answer 1

That is because,

Chlorine has atomic number 17, it only needs 1 electron to complete its octat, thus cl has valency -1.

and,

Potassium has atomic number of 19 and it need to loose 1 electron to be donated, thus it has the valency of +1.

And together Chlorine and potassium forms Potassium chloride, because the donated electron of potassium it taken by the chlorine.

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