# Q. If 'l'``` ` can have (n+1) no. of values,then electronic configuration of `_11Na` is A) `[Ne]3s^1` B) `[He]1p^6 2s^2 2p^1` C) `[O]2s^2 2p^1` D) `[Ne]2s^2 2p^6 3s^1`

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If 'l', the azimuthal quantum number, can have (n+1) values then 'l' would have assumed the values of 0,1,...........,n (where n is the principal quantum number).

For n=1, l=0,1 corresponding orbital designations (1s,1p)

For n=2, l=0,1,2 corresponding orbital designations (2s,2p,2d)

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And the element with first inert gas configuration would then be O(8) `rarr 1s^2 1p^6.`

The electronic configuration of `Na_11` would then be:

`[1s^2 1p^6] 2s^2 2p^1`

`=[O]2s^2 2p^1.`

Therefore, **option c)** is the correct answer.

In actual practice, however, 'l' can assume n values ranging from 0 to (n-1).

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