Question

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

Explanation:

Step1: Recall fluorine's atomic number

Fluorine has an atomic number of 9, so it has 9 electrons.

Step2: Apply electron - filling rules

Electrons fill orbitals in the order 1s, 2s, 2p. The 1s orbital can hold 2 electrons, the 2s orbital can hold 2 electrons, and the 2p orbital can hold 6 electrons. First, 2 electrons go into 1s, then 2 into 2s, and the remaining 5 into 2p. According to Hund's rule, electrons in degenerate (same - energy) orbitals (the three 2p orbitals) first fill each orbital singly with parallel spins before pairing up.

Answer:

The first option (where 1s has 2 paired electrons, 2s has 2 paired electrons, and 2p has 5 electrons with one orbital having 2 paired electrons and the other two having 1 unpaired electron each) shows the correct electron - configuration for fluorine.