Question

The period number in the long form of the periodic
table is equal to
(a) magnetic quantum number of any element of
the period.
(b) atomic number of any element of the period.
(c) maximum Principal quantum number of any
element of the period.
(d) maximum Azimuthal quantum number of any
element of the period.

Answer 1

Answer:

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Answer 2

(c) maximum Principal quantum number of any element of the period.

Explanation:

Each period starts with the filling of electrons in a new principal quantum number. So the period number in the long form of the periodic table refers to the maximum principal quantum number of any element in the period. Period number = maximum n of any element where n is the principal quantum number.

Option C is the answer.