The reactivity of fluorine is due to?

Analysis

The question asks for the primary reason behind the extreme reactivity of fluorine compared to other halogens in Group 7 of the periodic table.

Concept Explanation

Fluorine is the most electronegative and the most reactive non-metal in the periodic table. To understand its reactivity, we look at two main factors:

1. Electronegativity: This is the tendency of an atom to attract a shared pair of electrons in a covalent bond. Fluorine has the highest electronegativity of all elements (4.0 on the Pauling scale). Because it pulls electrons so strongly, it reacts vigorously with almost any substance it encounters.
2. Bond Dissociation Energy: While fluorine is small, the F-F bond is actually surprisingly weak compared to other halogens (like Cl-Cl) due to the repulsion between the lone pairs of electrons on the small fluorine atoms. This makes it very easy to break the bond and initiate a reaction.

However, in the context of standard chemistry examinations like JAMB, the high electronegativity is the fundamental property that drives its ability to gain an electron and form bonds, making it the most reactive element in the group.

Step-by-Step Solution

1. Examine Option A: Electronegativity is the measure of an atom's ability to attract electrons. Since fluorine has the highest electronegativity, it has the strongest drive to complete its valence shell, making it highly reactive.
2. Examine Option B: While the small size contributes to the high electronegativity, "high electronegativity" is the more direct chemical explanation for its reactivity.
3. Examine Option C: Fluorine is in the second period and does not have d-orbitals. This is factually incorrect.
4. Examine Option D: The F-F bond is weak, but the reactivity of the element itself is defined by its electronic nature (electronegativity) rather than just the bond strength of the diatomic molecule.

Comparing these, the most comprehensive reason for fluorine's chemical behavior is its extreme electronegativity.

Conclusion

This aligns with the chemical principle that fluorine's position as the most electronegative element is the primary driver of its chemical reactivity.

Exam Tip

Remember the acronym FONCl (Fluorine, Oxygen, Nitrogen, Chlorine). These are the most electronegative elements in order. Fluorine is the "king" of electronegativity—whenever you see a question about why fluorine is so reactive or why it forms such strong ionic bonds, look for "electronegativity" as your keyword!