For neutral molecules,No. of electron pairs = No. of atoms bonded to it + 1/2[Gp.no of central atom-Valency of central atom] ∴ For CH4 no of e− pairs=4+
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[4−4]=4(sp3) For SF4 no of e− pairs =4+
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[6−4]=5(sp3d) For ions, Nof electron pairs = NO of atoms bonded to it +1/2[G.P . no. of central atom - Valency of central atom ± No of electrons] ∴ For BF4−,no of e− pairs =4+
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[3−4+1]=4(sp3) hybridisation For NH4+,no of e− pairs =4+