Polar vs Non polar

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Roni Touboul
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Joined: Fri Sep 28, 2018 12:24 am

Polar vs Non polar

Postby Roni Touboul » Sun Nov 11, 2018 2:36 pm

How do you know when something is polar or non polar? What are some identifying factors used to figure it out?

Lily Benitez 2G
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Joined: Fri Sep 28, 2018 12:29 am

Re: Polar vs Non polar

Postby Lily Benitez 2G » Sun Nov 11, 2018 2:52 pm

To figure out if something is polar or non polar we have to look at the dipole moments. If the dipole moments cancel each other out the compound is non polar. In contrast if there is a strong dipole moment the compound is polar.

mcredi
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Joined: Fri Sep 28, 2018 12:16 am

Re: Polar vs Non polar

Postby mcredi » Sun Nov 11, 2018 3:09 pm

If the electronegativity of two atoms is basically the same, a nonpolar covalent bond will form, and if the electronegativity is slightly different, a polar covalent bond will form.

Jaqueline Monreal 2L
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Joined: Fri Sep 28, 2018 12:28 am

Re: Polar vs Non polar

Postby Jaqueline Monreal 2L » Sun Nov 11, 2018 4:29 pm

polar molecules result from polar bonding between atoms where electrons are not shared equally
atoms from the same element do not form polar bonds because they share electrons equally
the greater the difference in electronegativity then the more ionic the bond is and bonds that have ionic bonds
nonpolar covalent bonds happen when the two atom's electronegativities are equal

905096106
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Joined: Fri Oct 05, 2018 12:17 am

Re: Polar vs Non polar

Postby 905096106 » Sun Nov 11, 2018 7:57 pm

Polar versus nonpolar is very difficult to determine but it is based off of the difference in electronegativity between the atoms in a molecule. usually if the molecule is very symmetrical with its lewis dot structure then it will be nonpolar.

davidbakalov_lec2_2L
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Joined: Fri Sep 28, 2018 12:23 am

Re: Polar vs Non polar

Postby davidbakalov_lec2_2L » Sun Nov 11, 2018 8:02 pm

A quick rule of thumb to determine the polarity of a molecule is to look at how symmetrical it is. If the arrangement of the atoms is symmetrical, it will most likely be non polar.

Andrew Bennecke
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Joined: Fri Sep 28, 2018 12:15 am

Re: Polar vs Non polar

Postby Andrew Bennecke » Mon Nov 12, 2018 10:02 am

To tell whether a molecule is polar or nonpolar, one could look at whether or not the dipoles cancel, the electronegativity, and whether or not the electron pull of each atom is symmetrical. For example, in F2, the electrons of each F atom have the same pull, so it is a nonpolar molecule. However, in HCl, the Cl has a much stronger pull than the H, so this would be a polar covalent bond.

Nawaphan Watanasirisuk 3B
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Joined: Tue Nov 28, 2017 3:03 am

Re: Polar vs Non polar

Postby Nawaphan Watanasirisuk 3B » Wed Nov 14, 2018 3:52 pm

It depends on the difference in electronegativity of the atoms. C-H for example have similar electronegativity and therefore is nonpolar because electrons are shared equally between the 2 atoms.

Angela Grant 1D
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Joined: Fri Sep 28, 2018 12:25 am

Re: Polar vs Non polar

Postby Angela Grant 1D » Wed Nov 14, 2018 3:56 pm

This is what my high school chem teacher taught us: "A molecule with a uniform distribution of electron density is nonpolar; and one with an asymmetrical distribution is polar. A molecule is nonpolar only if it has no lone pair electrons about the central atom and all groups attached to the central atom are identical (both conditions must be met to be nonpolar). Another way to state this is if the electron group and molecular shapes are the same and the atoms attached to the central atom are identical, then the molecule is nonpolar."

mbaker4E
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Joined: Fri Sep 28, 2018 12:26 am

Re: Polar vs Non polar

Postby mbaker4E » Wed Nov 14, 2018 4:14 pm

The molecule will most likely be polar if there are different atoms around the central atom. A molecule will most likely be nonpolar if the molecule is symmetrical and has the same atoms around the central atom.

Nina Do 4L
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Joined: Fri Sep 28, 2018 12:27 am

Re: Polar vs Non polar

Postby Nina Do 4L » Wed Nov 14, 2018 5:13 pm

When you determine that the atom is polar or non polar (from the previous comments), the direction of polarity points to the atom that is most electromagnetic! :)

705022748
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Joined: Fri Sep 28, 2018 12:25 am

Re: Polar vs Non polar

Postby 705022748 » Thu Nov 15, 2018 9:10 pm

To determine whether or not a molecule is polar or nonpolar, you have to consider the electronegativity between atoms, and if the atoms are symmetrical, it would most likely be nonpolar.

605308157
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Joined: Sat Aug 17, 2019 12:17 am

Re: Polar vs Non polar

Postby 605308157 » Wed Oct 02, 2019 4:32 pm

A polar molecule is when there are slight positive and/or negative charges within the atoms. This is formed when one of the atoms tends to attract the electrons more than the others due their electronegativity levels. Hydrogen and Carbon tend to have low electronegativity levels that is why all hydrocarbons are considered non polar. Meanwhile, Oxygen and Nitrogen have high electronegativity levels which explains why water is a polar molecule because oxygen attracts the electrons more than the hydrogen; thus making oxygen slightly negative and hydrogen slightly positive. Hydrogen bonds occur only if the hydrogen is paired with an element with high electronegtaivity, thus molecules that can form hydrogen bonds with water are considered polar and those that can't are nonpolar.

annikaying
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Joined: Sat Sep 14, 2019 12:16 am

Re: Polar vs Non polar

Postby annikaying » Wed Oct 09, 2019 3:33 pm

Polar molecules have an uneven hold on the electrons whereas in non polar molecules the electrons are shared equally or mostly equally. You can tell just by looking at the electronegativity differences of the certain elements.

Manav Govil 4A
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Joined: Sat Sep 07, 2019 12:19 am

Re: Polar vs Non polar

Postby Manav Govil 4A » Thu Oct 10, 2019 8:27 pm

I love polar vs nonpolar stuff!

The polarity of a compound depends on the charges and electronegativity of its structure. The electronegativity of atoms can be found on a periodic table such as this:

http://www.thecatalyst.org/electabl.html

Using the values from the periodic table above, you can measure how polar a compound is.

For example, let's take HF, H20 and CH

We would calculate the polarity of HF by taking the electronegativity of F and subtracting it by the electronegativity of H: 4.0 - 2.1 = 1.9.

CH: 2.5 - 2.1 = 0.4

H20: 3.5 - 2.1 = 1.4

After getting these values, we would align them within a line that gives us ranges of polarity. The following is data that describes this line from https://www.chemteam.info/Bonding/Elect ... arity.html:

I. Nonpolar Covalent: This type of bond occurs when there is equal sharing (between the two atoms) of the electrons in the bond. Molecules such as Cl2, H2 and F2 are the usual examples.

Textbooks typically use a maximum difference of 0.2 - 0.5 to indicate nonpolar covalent. Since textbooks vary, make sure to check with your teacher for the value he/she wants. The ChemTeam will use 0.5.

One interesting example molecule is CS2. This molecule has nonpolar bonds. Sometimes a teacher will only use diatomics as examples in lecture and then spring CS2 as a test question. Since the electronegativities of C and S are both 2.5, you have a nonpolar bond.

II. Polar Covalent: This type of bond occurs when there is unequal sharing (between the two atoms) of the electrons in the bond. Molecules such as NH3 and H2O are the usual examples.

The typical rule is that bonds with an electronegativity difference less than 1.6 are considered polar. (Some textbooks or web sites use 1.7.) Obviously there is a wide range in bond polarity, with the difference in a C-Cl bond being 0.5 -- considered just barely polar -- to the difference the H-O bonds in water being 1.4 and in H-F the difference is 1.9. This last example is about as polar as a bond can get.

III. Ionic: This type of bond occurs when there is complete transfer (between the two atoms) of the electrons in the bond. Substances such as NaCl and MgCl2 are the usual examples.

The rule is that when the electronegativity difference is greater than 2.0, the bond is considered ionic.

So, in our cases, the CH bond is nonpolar, while H20 and HF are polar.

I hope this helped!!!!!

Shutong Hou_3I
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Joined: Sat Sep 14, 2019 12:17 am

Re: Polar vs Non polar

Postby Shutong Hou_3I » Fri Oct 11, 2019 11:05 am

If the electronegativity difference between two atoms is large, the molecular formed by the two atoms would be polar; if he difference is subtle or zero, then the molecule is nonpolar. If the molecule is a long chain composed of many (mostly four or more) carbons and hydrogens, as well as very few (frequently one) atoms that are very electronegative, the molecule would still be overall nonpolar, but with a polar region.


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