Question

which diagram shows the correct electron configuration for fluorine (f)?

Explanation:

Identify atomic number of fluorine

Fluorine (\(\text{F}\)) has an atomic number of 9, meaning a neutral fluorine atom has 9 electrons.

Determine correct orbital filling

Following the Aufbau principle, Hund's rule, and the Pauli exclusion principle:

• The \(1s\) orbital holds 2 electrons: \(\uparrow\downarrow\)
• The \(2s\) orbital holds 2 electrons: \(\uparrow\downarrow\)
• The remaining 5 electrons fill the three \(2p\) orbitals: two orbitals are fully filled with 2 electrons each, and one orbital has 1 electron: \(\uparrow\downarrow\ \uparrow\downarrow\ \uparrow\)

Match with given options

• Option 1 shows \(1s^2\ 2s^2\ 2p^5\) with two paired \(2p\) orbitals and one unpaired \(2p\) orbital. This is correct.
• Option 2 shows \(1s^2\ 2s^2\ 2p^4\) with one empty \(2p\) orbital, which violates Hund's rule and has only 8 electrons.
• Option 3 shows \(1s^2\ 2s^2\ 2p^3\) with only 7 electrons (nitrogen configuration).

Answer:

• (A) First diagram: 1s with 2 electrons, 2s with 2 electrons, 2p with 5 electrons (two paired, one unpaired) (Correct answer)
• (B) Second diagram: 1s with 2 electrons, 2s with 2 electrons, 2p with 4 electrons (two paired, one empty)
• (C) Third diagram: 1s with 2 electrons, 2s with 2 electrons, 2p with 3 electrons (three unpaired)