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Is Methane Nonpolar?

Methane is the simplest carbon compound found naturally in waste. Methane is also combustible, but it is nontoxic when inhaled, although it can reduce oxygen consumption, causing suffocation. Methane is a symmetric molecule with the formula CH4, meaning it contains one carbon and four hydrogen atoms. When used as a fuel, methane combined with oxygen forms one carbon dioxide molecule and two water molecules. Methane is tetrahedral, and understanding its polarity involves understanding polarity, bonding and dipole cancellation.

  1. Bonds

    • Bonds connect two atoms together to form a molecule. The main types of bonds (besides metallic and hydrogen) are ionic and covalent bonding. Ionic bonds happen when an electron is removed from an atom, creating positive and negative ions. Covalent bonds involve the sharing of electrons between atoms. This is the type of bond that is used within methane, and it is also the type of bond that forms polar and nonpolar molecules.

    Polarity

    • Polarity adds to bonding in the way that covalent electrons are distributed. Certain atoms on the periodic table are more electronegative than others. Fluorine is the most electronegative atom, and electronegativity weakens as you move to the left or down the periodic table of elements. Electronegativity plays a role in polarity. The stronger the electronegativity of an atom, the more it tends to pull electrons towards its center. In the case of methane, carbon is more electronegative than hydrogen, so electrons are pulled closer to the carbon than the hydrogen atom.

    Dipole Moment

    • The dipole moment of a molecule is a way to assess polarity. The dipole moment is that point in time when an atom is more negative than another that it's bonded with due to its affinity to pull its shared electron closer to it. The dipole moment is an important part of molecular interactions with electrons. The dipole moment is only active when the electron is closest to the atom, and it determines the molecular shape.

    Geometry

    • The last part in understanding the polarity of methane is its geometry. Methane is tetrahedral, which means the carbon sits in the center of the molecule while the four carbons are situated in a way that forms 109-degree bond angles. The hydrogen atoms uniformly surround the carbon molecule so that it keeps them the farthest possible distance away from each other. This is because the hydrogen atoms repel each other, forming the bond angles in its geometry.

    Methane's Polarity

    • All of these factors play a role in methane's polarity. Although the carbon and hydrogen atom covalently bonded are polar, the four atoms that uniformly surround the carbon atom cancel out the dipole moments of the other bonds. Methane has a dipole moment of zero, so although the bonds are polar, the overall polarity of methane is zero, making it nonpolar.

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