Polar Bonds [ENDORSED]

[Trevor_Ramsey_3H]

Hi, How are you able to determine if a molecule contains polar bonds just by looking at the structure and its atoms.

[Sharon Kim 2A]

Usually you should look for symmetry and atoms that have different electronegativities within the structure. If dipole moments do not cancel it is safe to assume there are polar bonds.

[Alexandra Ahlschlager 1L]

You can determine this by looking at the differences in electronegativity between the atoms; atoms with a large difference in electronegativity will create a dipole and cause the molecule to be polar. For example, in an HF molecule, the large difference in electronegativity would cause electrons to be pulled toward the fluorine atom, generating a dipole and making the molecule polar. Hope this helps!

[SelenaDahabreh1D]

Also, it is helpful to look at lone pairs. I remember there was a problem in the textbook in which we were asked to draw the figure of AsF3 and AsF5. And since the dipole moments cancelled out in AsF3, it was considered to have a lower boiling point because it was no longer polar. On the other hand, AsF3 had a higher boiling point because it had one lone pair so the dipoles did not entirely cancel out.

[Lesly Lopez 3A]

Hi,

The way I do it is to look at the differences in electronegativity between the atoms on the periodic table. When the atoms with a large difference in electronegativity compared to each other then this will create a dipole moment. This is what will cause the molecules to be polar. The large difference in electronegativity would cause electrons to be pulled toward the the low electronegativity atom, forming a dipole and making the molecule polar.

[Maya Johnson 2a]

Hi,
I usually look for lone pairs or symmetry when looking to see if a molecule is polar or not. Also, I look to see if the central atom has all the same types of atoms surrounding it, as sometimes if one is more electronegative than the other it cause cause a slight pull of e-.

[simona_krasnegor_1C]

For this, I tend to look at electronegativity and the presence of lone pairs in the lewis structure. Based off of this, we can see which atom wants electrons more and therefore we can see the sharing is not exactly equal, creating a dipole.

[Crystal Pan 2G]

You would draw the dipole moments on the lewis structure(by determining en) and then using vector addition, you could see which of the dipole moments cancel.

[Kevin Pilcher 3J]

The key thing I look for is symmetry in the molecule and after that, I look at the charges. If there is symmetry in both the bonds and charges within the molecule it is likely nonpolar.

[Vince Li 2A]

You would look at the dipoles of the molecules. Remember when Dr. Lavelle mentioned partial positive and partial negative charges. To determine if a molecule is polar, there are multiple strategies you can use. First, you could determine the Lewis dot structure. By looking at the dot structures, you will be able to see the lone pair locations. This is where electrons have the greater electron density, so for example when looking at an H2O molecules, you will see that there are two lone pairs on the Oxygen atom that are in a bent shape. Because the components of the dipole point towards the lone pairs, in that the Oxygen is more electronegative, there is a partial negative charge on the Oxygen and a partial positive charge on the Hydrogen. If the components of the dipoles are going in a specific direction, the molecule is polar.

[Mackenzie Van Val 3E]

If a molecule has a symmetric structure with all the same atoms around the central atom (for example, SF6), you can immediately tell that the molecule is non-polar, With molecules that have an asymmetric structure, you can look at the atoms within the molecule and use periodic trends to help you determine polarity; for example, we know O is extremely electronegative based on periodic trends, which can help us determine that H2O is polar. Also, if a molecule appears to have symmetric structure, but the atoms around the central atom are not the same (for example, in NSF3), then the molecule is likely polar because the charges will not cancel out to zero.

[Yolanda_Xing_3A]

I would look if the structure is symmetrical for not. If it is asymmetrical, then it is polar. Then use the periodic trends to determine the polarity.

[George Hernandez 3I]

By the looking at the structure, if the molecule is asymmetrical with bonding, electrons, etc, then it is always non-polar because that means that one side is slightly more positive/negative than the other.

[Megan ODonnell 3F]

Usually symmetry, and if you can determine the difference in electronegativities. If the shape of the molecule is mostly symmetrical it is more likely to be non polar.

[Annette Fishman]

I look at electronegativity and the presence of lone pairs in the Lewis structure. It is extremely helpful to also draw the atom and indicate all the lone pairs. If the molecule is asymmetrical with bonding, electrons, etc, then it is always non-polar because that means that one side is slightly more positive/negative than the other.

[105618850]

You should examine the dipole moments and observe if they cancel each other out. A more simple way of thinking about polarity is looking at the molecule's symmetry. At times, it will be pretty obvious but sometimes I double check using the scientific method rather than just relying on the visual method.

[105618850]

You should examine the dipole moments and observe if they cancel each other out. A more simple way of thinking about polarity is looking at the molecule's symmetry. At times, it will be pretty obvious but sometimes I double check using the scientific method rather than just relying on the visual method.

[Joshua Swift]

If the molecule has different atoms bonded to each other, it will be polar. However, the geometry of a molecule can cancel out these polar bonds and make it nonpolar due to its symmetry.

[Joshua Chung 2D]

You look at the geometry and the differences in electronegativity. If there are clear differences that do not cancel out, then the bond is polar.

[Yuehan_Wu_3K]

If the structure is symmetric, then it's polar.

[oliviahelou]

To know if a molecule is polar, you need to compare the electronegativities of the different atoms in the molecule

[Jane Wang 1E]

Hi, How are you able to determine if a molecule contains polar bonds just by looking at the structure and its atoms.

If the atoms have great difference in their electronegativity, then the bond is polar.

[sophiavmr]

I think that you have to compare the electronegativites between the two atoms. For example O is a much more electronegative atom than H, so it will be a polar bond between them. A general rule for electronegativity that I have seen is that H=C<O=N

[Kati Rady-Pentek 1E]

Polar bonds will occur when two atoms with a significantly different electronegativity bond. The electrons of the less electronegative atom will cluster nearer towards the more electronegative atom, causing a partial negative and positive charge on the atoms.

[Rhea Jain 2I]

You would have to look at the difference in electronegativity between the two atoms. If one is more electronegative than the other, it is a polar bond.

[Alexis Rempillo 3B]

This is what I know so far from my LS7A course, is that if there is an atom with a high electronegativity e.g. oxygen and there was an atom connected to it with a lower electronegativity, then the bond between them is polar. Electronegativity is sorta like an atom's ability to attract electrons. Since oxygen has a higher electronegativity than say hydrogen (low electronegativity), then their bonds are polar. Just like how water is a polar molecule. The electrons of the hydrogen are more attracted to the oxygen atom, this makes the oxygen atom partially negative, and the hydrogen atoms partially positive. When it has these partial charges then it is polar.

[Samantha Quevedo 2L]

Hello! Just by looking at the structure, if there is symmetry then the molecule is nonpolar. If it is nonsymmetrical then the molecule is polar.