Question 4 - Past Year - 1 Mark Questions - Chapter 5 Class 10 - Periodic Classification of Elements

How does valency of an element vary across a period?

Answer

Valency is equal to the number of valence electrons. In the modern periodic table, valency first increases till the number of valence electrons is 4. After that, it decreases as we keep moving right.

Therefore,  as we move from left to right in a period, valency first increases then decreases .