Polarity of Methane (CH4)
Methane (CH4) has a central carbon (C) atom that is covalently bonded to four hydrogen (H) atoms. The shape of methane is tetrahedral with a bond angle of 109.28°. The electronegativity of carbon is 2.55, and that of hydrogen is 2.18. Since carbon is more electronegative than hydrogen, it pulls the shared electron pairs toward itself. Therefore, it acquires a partial positive charge, and the hydrogen acquires a partial negative charge. This difference in the charge distribution makes the C-H bond polar [1-4].
However, the methane molecule has a symmetrical shape. While each C-H bond has a dipole moment, the symmetry cancels all the dipole moments. Therefore, the net dipole moment of CH4 is zero, making it nonpolar.