Question

The period to which an element belongs to in the long form of periodic table represents :

• A. atomic mass
• B. atomic number
• C. principal quantum number
• D. azimuthal quantum number

Answer 1

The correct option is C principal quantum number

n is the principal quantum number or number of shells. It represents the number of periods to which an element belongs to. Thus, $n=1$ represents first period, $n=2$ represents second period and $n=3$ represents third period. Hence periodic table is arranged on the basis of the electronic configuration of elements.

Hence, option $C$ is correct.