Question

Using the image above, explain why picture 'D' is not a valid orbital notation diagram for fluorine.

• A. There are not enough electrons in the picture.
• B. The diagram does not properly display $7$ valence electrons.
• C. The diagram shows $2$ electrons with the same spin.
• D. The diagram is actually correct and valid.

Answer 1

Answer: (C)

The diagram shows $2$ electrons with the same spin.

Hund's Rule states that every orbital in a subshell is singly occupied with one electron before any one orbital is doubly occupied, and all electrons in singly occupied orbitals have the same spin (all up or all down).

Fluorine has 9 electrons and its electronic configuration is $1s^{2}2s^{2}2p^5$ Thus figure d has same number of electrons, but in one of the $2p$ orbital both electrons are of same spin and is therefore donot follow the rule.

option C is correct