Shapes of Molecules

The theory does not explain the geometrical shapes of molecules. For instance, it cannot clarify why water (H₂O) has a bent shape or why methane (CH₄) forms a tetrahedral structure.

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2. Bond Strength

It fails to explain differences in bond strength. For example, it cannot address why double bonds are stronger than single bonds but weaker than triple bonds

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3. Transition Elements

The theory is inadequate for transition elements, which involve d-orbitals. It does not explain variable valency or metallic bonding observed in these elements.

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4. Octet Rule Exceptions

The theory overemphasizes the octet rule, ignoring molecules that violate it:

• Incomplete octet: Boron trifluoride (BF₃).
• Expanded octet: Sulfur hexafluoride (SF₆).

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5. Neglect of Quantum Mechanics

It does not incorporate quantum mechanical principles such as hybridization, which explains molecular shapes, or molecular orbital theory, which addresses bonding in detail.

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6. Resonance

The theory cannot explain resonance, where a molecule has multiple valid structures, such as benzene (C₆H₆) and ozone (O₃).