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VBT explains covalent bonding through overlap of atomic orbitals. Hybridisation is the mixing of s, p, and d orbitals to produce equivalent hybrid orbitals directed in specific spatial arrangements. The hybridisation of any atom equals its steric number: sigma bonds + lone pairs. sp (SN=2, linear), sp2 (SN=3, trigonal planar), sp3 (SN=4, tetrahedral), sp3d (SN=5, TBP), sp3d2 (SN=6, octahedral). Sigma bonds form from head-on overlap (allow rotation); pi bonds from lateral overlap of unhybridised p-orbitals (restrict rotation). A single bond = 1 sigma. A double bond = 1 sigma + 1 pi. A triple bond = 1 sigma + 2 pi. The percentage s-character affects bond properties: higher s-character means shorter, stronger bonds and larger bond angles. sp has 50% s-character (shortest bonds), sp3 has 25% (longest). Bent's rule adds nuance: electronegative substituents prefer hybrid orbitals with more p-character, while lone pairs occupy orbitals with more s-character. VBT successfully predicts molecular geometry and bond types but fails to explain O2's paramagnetism — it predicts all electrons paired in O=O.