Polar/non polar molecules

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Shreya Tamatam 3B
Posts: 30
Joined: Fri Sep 28, 2018 12:25 am

Polar/non polar molecules

Postby Shreya Tamatam 3B » Thu Nov 15, 2018 10:50 pm

How can you tell if a molecule is polar or non polar?

anthony_trieu2L
Posts: 60
Joined: Fri Sep 28, 2018 12:29 am

Re: Polar/non polar molecules

Postby anthony_trieu2L » Thu Nov 15, 2018 10:55 pm

You can determine if a molecule is polar or nonpolar based on its shape. For example, if the shape of the molecule is symmetric and it presents an even distribution of electron densities, then it is most likely nonpolar (and vice versa).

timschaeffer Dis 1J
Posts: 38
Joined: Fri Sep 28, 2018 12:18 am

Re: Polar/non polar molecules

Postby timschaeffer Dis 1J » Thu Nov 15, 2018 11:10 pm

Molecules are non-polar if they:

A) consist entirely of atoms of the same element
B) consist of a central atom of element 1 and a set of attached atoms that are all element 2, but the element 2 atoms are all symmetrically spaced around the molecule

Molecules are generally polar if they:

A) consist of only two atoms of different elements that have different electronegativities
B) have a molecular shape that is asymmetrical
C) have a symmetrical shape but there is more than one type of atom attached to the central atom

Nada AbouHaiba 1I
Posts: 77
Joined: Fri Sep 28, 2018 12:28 am
Been upvoted: 1 time

Re: Polar/non polar molecules

Postby Nada AbouHaiba 1I » Thu Nov 15, 2018 11:36 pm

another way of looking at this is by looking at the types of bonds.
a molecule is most likely polar is has polar bonds, as in an atom with high EN is bonded to something with low EN.
a nonpolar molecule will compose of nonpolar bonds is two atoms with similar EN

Tinisha 1G
Posts: 69
Joined: Fri Sep 28, 2018 12:17 am

Re: Polar/non polar molecules

Postby Tinisha 1G » Fri Nov 16, 2018 11:40 am

A main thing to look out for is if the pulls from the electronegative atoms cancels out. If they do, it’s non polar, if they don’t it’s polar. You need to look at the shape and see if there is an uneven distribution of electrons.

Michael Novelo 4G
Posts: 64
Joined: Fri Sep 28, 2018 12:28 am

Re: Polar/non polar molecules

Postby Michael Novelo 4G » Fri Nov 16, 2018 1:18 pm

You can tell if a molecule is polar or non polar based on its molecular shape. If the shape is symmetric then it is considered nonpolar and if it is not symmetric to the central atom its considered polar. When the molecule is not symmetric it is because the dipole moments do not cancel out with one another. When the molecular shape is symmetric it makes sense because the dipole moments between two atoms cancel out. The best way to understand this is by an illustration using a molecular shape such as NH3 you'll notice when you draw out its shape N acts as the central atom and has bonded separately with 3 hydrogen atoms. These 3 bonded hydrogens are an exception to the octet rule so they only required a bond with N so a lone pair of electrons are attached to N. The lone pair causes a repulsion causing the Hydrogen atoms to come close together. The dipole moments do not cancel out and the molecular shape is not symmetric so it is polar. An example of nonpolar is PCl5 it is symmetric and dipole moments cancel out.


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