Valency varies gradually across a period.

Valency varies gradually across a period.

Ans. 1. In the modern periodic table, the elements are arranged in increasing order of atomic number (Z).

2. Atomic number is related to the electronic configuration.

3. As the atomic number increases, the number of valence electrons increases. The first element has one electron in its outermost shell while the last element in a period has either completed duplet or octet.

4. So, valency varies gradually across a period.