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Polar Bonds and Molecular Shape

A polar molecule is a molecule that has a net dipole moment due to its having unsymmetrical polar bonds. There are two factors that go into determining if a molecule is polar or not. To determine if a molecule (or ion) is polar or non-polar, you must determine both factors.

  • The polarity of the individual bonds in the molecule.
  • The shape or geometry of the molecule.

First, to determine if a given individual bond is polar, you need to know the electronegativity of the two atoms involved in that bond. To find the electronegativities of all the elements, look at the Periodic Table (follow the link below this answer under Web Links).

If the electronegativity of the two atoms has a difference of 0.3 or less, then the bond is non-polar. If the electronegativity difference is greater that 0.3 but less than 1.7, then the bond is polar. If the two values have a difference greater than 1.7, then the bond is ionic, which is just very very polar.

Once you know which bonds in the molecule are polar and which are non-polar, you must use the shape of the molecule. You need the shape because two polar bonds, if oriented correctly can cancel each other out (like two equally strong people pulling in opposite directions on a rope -- nobody moves).

The three possible outcomes:

  • If all bonds are non-polar, then the whole molecule is non-polar regardless of its shape.
  • If there is symmetry in the molecule so that the polarity of the bonds cancels out, then the molecule is non-polar. A common example of this is carbon dioxide, or CO2. The molecule is linear, and its Lewis dot structure is like this: O=C=O (this doesn't include two sets of lone pairs on each oxygen). The carbon-oxygen bond is a polar bond, but because they are exactly opposed to each other, the molecule is overall non-polar. Another example of this is CCl4, where each carbon-chlorine bond is polar, but the molecule is non-polar. Here, how they cancel out isn't as obvious, but they do. CCl4 is a tetrahedral molecule, and the 4 C-Cl polar bonds cancel each other out.
  • If there are polar bonds but there is no symmetry such that they cancel each other out, the overall molecule is polar. Water is a typical example of this. The two O-H bonds are oriented in a V-shape, and so the don't cancel out. Similarly, CH3Cl is also polar. It is the same shape as CCl4 (see above), but now it doesn't have the same symmetry because there is only one C-Cl bond and the bonds don't cancel out anymore.
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Is lactic acid a polar or nonpolar molecule?

Lactic acid is a polar molecule. It contains both polar (-OH) and nonpolar (CH3) groups, but the presence of the polar -OH groups makes it an overall polar molecule.


What is the relationship between bond polarity and molecular polarity?

The relationship between bond polarity and molecular polarity is that the overall polarity of a molecule is determined by the polarity of its individual bonds. If a molecule has polar bonds that are not symmetrical, the molecule will be polar overall. If a molecule has nonpolar bonds or symmetrical polar bonds that cancel each other out, the molecule will be nonpolar overall.


How can one determine if a molecule is polar or nonpolar without relying on electronegativity values?

One way to determine if a molecule is polar or nonpolar without relying on electronegativity values is to consider its molecular geometry. If a molecule has a symmetrical shape and the individual bond dipoles cancel each other out, then the molecule is nonpolar. On the other hand, if the molecule has an asymmetrical shape and the bond dipoles do not cancel out, then the molecule is polar.


Is Fe2O3 polar or nonpolar?

Fe2O3 (iron oxide) is a nonpolar molecule because it has a symmetrical arrangement of its polar covalent bonds. The dipole moments in these bonds cancel each other out, resulting in a nonpolar overall molecule.


CH3Br polar or nonpolar?

CH3Br is a nonpolar molecule. Although the C-Br bond is polar due to the electronegativity difference between carbon and bromine, the overall molecule is nonpolar because of its symmetrical tetrahedral molecular geometry.

Related Questions

Is lactic acid a polar or nonpolar molecule?

Lactic acid is a polar molecule. It contains both polar (-OH) and nonpolar (CH3) groups, but the presence of the polar -OH groups makes it an overall polar molecule.


What is the first thing you should do if you want to determine if a molecule is polar or not?

Check the molecular geometry to determine if the molecule is asymmetrical. If the molecule has a symmetrical shape, it is likely nonpolar. If it is asymmetrical, check for polar bonds and the overall molecular polarity.


What is the relationship between bond polarity and molecular polarity?

The relationship between bond polarity and molecular polarity is that the overall polarity of a molecule is determined by the polarity of its individual bonds. If a molecule has polar bonds that are not symmetrical, the molecule will be polar overall. If a molecule has nonpolar bonds or symmetrical polar bonds that cancel each other out, the molecule will be nonpolar overall.


How can one determine if a molecule is polar or nonpolar without relying on electronegativity values?

One way to determine if a molecule is polar or nonpolar without relying on electronegativity values is to consider its molecular geometry. If a molecule has a symmetrical shape and the individual bond dipoles cancel each other out, then the molecule is nonpolar. On the other hand, if the molecule has an asymmetrical shape and the bond dipoles do not cancel out, then the molecule is polar.


How can a molecule nonpolar overall and still contain polar bonds?

Yes, a molecule can be nonpolar when it contains polar covalent bonds, because think about it. if the molecule is linear in structure, and it has two equally polar bonds on either side, then the polarity will essentially cancel out, and it will become nonpolar.


Is Fe2O3 polar or nonpolar?

Fe2O3 (iron oxide) is a nonpolar molecule because it has a symmetrical arrangement of its polar covalent bonds. The dipole moments in these bonds cancel each other out, resulting in a nonpolar overall molecule.


CH3Br polar or nonpolar?

CH3Br is a nonpolar molecule. Although the C-Br bond is polar due to the electronegativity difference between carbon and bromine, the overall molecule is nonpolar because of its symmetrical tetrahedral molecular geometry.


How can one determine if a bond is polar or nonpolar without relying on electronegativity?

One can determine if a bond is polar or nonpolar by looking at the symmetry of the molecule. If the molecule is symmetrical and the atoms on either side of the bond are the same, the bond is likely nonpolar. If the molecule is asymmetrical or the atoms on either side of the bond are different, the bond is likely polar.


Is the molecule co polar or nonpolar?

The molecule is nonpolar.


What is the relationship between molecular polarity and bond polarity?

Molecular polarity is determined by the overall arrangement of polar bonds within a molecule. If a molecule has polar bonds that are arranged symmetrically, the molecule is nonpolar. However, if the polar bonds are arranged asymmetrically, the molecule is polar. Therefore, the relationship between molecular polarity and bond polarity is that the presence and arrangement of polar bonds within a molecule determine its overall polarity.


Is an polar molecule an ion?

No a molecule is a molecule, polar or nonpolar.


Is phenyl salicylate a ionic polar or non polar bond?

Phenyl salicylate has covalent bonds, which are typically nonpolar. The molecule is symmetrical and contains nonpolar functional groups, making it nonpolar overall.