Question

how does valency vary in a group and period in the periodic table ​

Answer 1

$\Large{\underline{\underline{\tt{\purple{Hello !!}}}}}$

The valency of an element is dependent on the number of electrons in the outermost shell of the electron. In a group all constituting elements will have the same valency because they all have the same number of electrons in the outer shells. Across the a period, the number however increase by 1.

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