Atomic Structure - Result Question 92
####68. In an atom, the total number of electrons having quantum numbers
(2014 Adv.)
$$ n=4,\left|m _l\right|=1 \text { and } m _s=-\frac{1}{2} \text { is } $$
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Answer:
Correct Answer: 68. (5)
Solution:
- PLAN This problem is based on concept of quantum number. Follow the following steps to solve this problem. Write all possible orbitals having combination of same principal azimuthal, magnetic and spin quantum number.
Then count the all possible electrons having given set of quantum numbers.
For $n=4$, the total number of possible orbitals are
According to question $\left|m _l\right|=1$, i.e. there are two possible values of $m _l$, i.e. +1 and -1 and one orbital can contain maximum two electrons one having $s=+\frac{1}{2}$ and other having $s=-1 / 2$.
So, total number of orbitals having ${\left|m _l\right|=1 }=6$
Total number of electrons having
$$ {\left|m _l\right|=1 \text { and } m _s=-\frac{1}{2} }=6 $$
