Apentix/AP Chemistry/Unit 2: Molecular and Ionic Compound Structure and Properties/Question
AP Chemistrymediummcq1 pt

Sulfur forms SF₆, which places twelve electrons around the central atom. Why can oxygen not form an analogous OF₆?

A.Oxygen's period 2 valence shell has only s and p orbitals, capping it at eight electrons
B.Oxygen is too electronegative to form more than two bonds
C.Six fluorine atoms cannot fit around such a small central atom
D.Oxygen has only two unpaired electrons, so it can never exceed two bonds

Explanation

Core Concept

Second-shell capacity stops at eight electrons because the n = 2 level supplies only 2s and 2p orbitals. Six O-F bonds would demand twelve electrons around oxygen, which that shell cannot hold. Sulfur sits one period lower, where expansion beyond an octet becomes possible, so SF₆ exists while OF₆ does not. The limiting factor is valence orbital availability, not electronegativity.

Correct Answer

AOxygen's period 2 valence shell has only s and p orbitals, capping it at eight electrons

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