Question

The location of any element in the periodic table is determined by the __________ of the filled last orbital.

(a) Spin quantum number

(b) Quantum numbers

(c) Azimuthal quantum number

(d) Magnetic quantum number

I had been asked this question in homework.

Origin of the question is Electronic Configurations of Elements and the Periodic Table in section Classification of Elements and Periodicity in Properties of Chemistry – Class 11

Answer 1

Right choice is (b) Quantum numbers

Explanation: Quantum numbers are responsible for an element’s position in the periodic table. For example, as we know the principal quantum number defines the main energy level i.e. shell. The last orbital principal quantum number is the periodic number of the element.