ANSWER
The oxidation number of fluorine (F) is -1
Step-by-step explanation
The given compound is NaF
To find the oxidation number of F, follow the steps below
Let x represents the oxidation number of F
Recall, that the oxidation number of Na is +1
Therefore, we can find the oxidation number below
1 + x = 0
subtract 1 from both sides of the equation
1 - 1 + x = 0 - 1
x = 0 - 1
x = -1
Therefore, the oxidation number of fluorine (F) is -1 N