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Omniscience
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How to distinguish between polar and nonpolar molecules/compound? For instance, one that you have not studied before but have to know if its polar or nonpolar. Can you distinguish it from the basic structure of the molecule?
For instance, Bromine Br_2; at first I thought it was polar but then its not nonpolar..so how can you tell?
 2 years ago
 2 years ago
Omniscience Group Title
How to distinguish between polar and nonpolar molecules/compound? For instance, one that you have not studied before but have to know if its polar or nonpolar. Can you distinguish it from the basic structure of the molecule? For instance, Bromine Br_2; at first I thought it was polar but then its not nonpolar..so how can you tell?
 2 years ago
 2 years ago

This Question is Closed

halcy0n Group TitleBest ResponseYou've already chosen the best response.0
You can instantly tell if a molecule is polar if you look at the electronegativity differences between two differing atoms. The larger the difference between electronegativity values, the more polar the molecule is.
 2 years ago

jwheele1 Group TitleBest ResponseYou've already chosen the best response.0
halcyon is right. Do you have an electronegativity chart? Some are different from others. IS there one in your text book? If not I can find you one, but its better to use what your teacher supplies you with.
 2 years ago

Omniscience Group TitleBest ResponseYou've already chosen the best response.0
But a nonpolar molecule would have an electrongativity differences as well; i think. and electronegativity charts are not provided in exams here is it possible to distinguish it from the structure of the molecule?
 2 years ago

jwheele1 Group TitleBest ResponseYou've already chosen the best response.0
Not sure about how to find the answer from structure. "But a nonpolar molecule would have an electrongativity differences as well; i think." You are right. The way you determine the status is to see to which degree of difference is apparent.
 2 years ago

Omniscience Group TitleBest ResponseYou've already chosen the best response.0
What if I dont know anything about the molecule; like if its polar or nonpolar how am i able to distinguish? If i remember correctly, you can determine it by the structure..but i cant remember how
 2 years ago

jwheele1 Group TitleBest ResponseYou've already chosen the best response.0
http://www.greenplanetsolarenergy.com/images/PTsmallelectroneg.gif
 2 years ago

jwheele1 Group TitleBest ResponseYou've already chosen the best response.0
What about this link: http://www.tutorhomework.com/Chemistry_Help/Molecular_Geometry/Polar_Or_Nonpolar.html
 2 years ago

Omniscience Group TitleBest ResponseYou've already chosen the best response.0
that will be hard tho; to remember the electronegativity of all elements..
 2 years ago

jwheele1 Group TitleBest ResponseYou've already chosen the best response.0
this is true....i dont think any teacher would expect that. With out the chart, that method is dead
 2 years ago

jwheele1 Group TitleBest ResponseYou've already chosen the best response.0
but it is easy
 2 years ago

jwheele1 Group TitleBest ResponseYou've already chosen the best response.0
with the chart
 2 years ago

jwheele1 Group TitleBest ResponseYou've already chosen the best response.0
all ionic bonds are polar right?
 2 years ago

jwheele1 Group TitleBest ResponseYou've already chosen the best response.0
what about this: http://preparatorychemistry.com/bishop_molecular_polarity.htm
 2 years ago

Omniscience Group TitleBest ResponseYou've already chosen the best response.0
well i would like a method without the electronegativity chart
 2 years ago

Omniscience Group TitleBest ResponseYou've already chosen the best response.0
(if possible)
 2 years ago

jwheele1 Group TitleBest ResponseYou've already chosen the best response.0
that last link i believe is that kind of method...without the chart
 2 years ago

Omniscience Group TitleBest ResponseYou've already chosen the best response.0
i read it..stil needs the chart
 2 years ago

jwheele1 Group TitleBest ResponseYou've already chosen the best response.0
lame...ok one sec
 2 years ago

halcy0n Group TitleBest ResponseYou've already chosen the best response.0
All ionic bonds are polar. Electronegativity differences are taken into account with covalent bonds. If it's a compound such as F2 then no, it's not polar cause of the same electronegativity
 2 years ago

jwheele1 Group TitleBest ResponseYou've already chosen the best response.0
I think I asked my teacher if there was a way and he said no...
 2 years ago

Omniscience Group TitleBest ResponseYou've already chosen the best response.0
well what if you dont know if its an ionic bond or not..how would you know if its polar or nonpolar?
 2 years ago

jwheele1 Group TitleBest ResponseYou've already chosen the best response.0
well metals and non metals make inonic bonds
 2 years ago

jwheele1 Group TitleBest ResponseYou've already chosen the best response.0
You can always make an educated guess if you know if an element is metal or non metal or if you know if an element is on the left or right or top or bottom of the per table
 2 years ago

jwheele1 Group TitleBest ResponseYou've already chosen the best response.0
bottom left is real small.....top right of table is real big
 2 years ago

jwheele1 Group TitleBest ResponseYou've already chosen the best response.0
Fr = 0.7 F = 4.0
 2 years ago

benjaminf Group TitleBest ResponseYou've already chosen the best response.0
It's entirely about the structure, like you were thinking! Basically symmetry means nonpolar and asymmetry means polar. So Br2 has two atoms with the same EN; you can imagine their electron withdrawing strength canceling out one another's pull so that there's no net pull in the structure and the whole thing is nonpolar. In contrast, something like CO would have a net polarity because even if you can't remember what the EN of C of O is, you still know that one half of that molecule is going to pull the electrons a little more than the other. That gives the molecule a net polarity. It helps if you just draw a little arrow pointing in the direction of the Electron withdrawing activity. Then you can see if there's a net pull or if there are arrows that cancel one another out.
 2 years ago

Gochi Group TitleBest ResponseYou've already chosen the best response.0
u cn find d difrnc simply by evaluatng d electronegativity o strucure. evn the aarangemnt in d periodic table l gv u an idea of the polarity b/w molecules,atoms,elemnts
 2 years ago

Omniscience Group TitleBest ResponseYou've already chosen the best response.0
okay, thanks benjaminf but for the structure; is it the molecular structure? the chemical formula structure or what? They just look symmetrical to me.
 2 years ago

Sheng Group TitleBest ResponseYou've already chosen the best response.1
it's based on what elements comprise the structure and also on the molecular structure.
 2 years ago

Omniscience Group TitleBest ResponseYou've already chosen the best response.0
well how can you see it from the molecular stucture?
 2 years ago

Sheng Group TitleBest ResponseYou've already chosen the best response.1
a simple way to see if you can make the 2 sides balance
 2 years ago

Omniscience Group TitleBest ResponseYou've already chosen the best response.0
For example, Bromine Br_2' how are able to balance/ see it?
 2 years ago

Sheng Group TitleBest ResponseYou've already chosen the best response.1
if you cut the molecule in 1/2, one side will have 1 Br and the other another Br, so it's balanced thus nonpolar
 2 years ago

Sheng Group TitleBest ResponseYou've already chosen the best response.1
so another example, NaCl, one side has Na other side Cl, 2 different elements, thus polar
 2 years ago

Sheng Group TitleBest ResponseYou've already chosen the best response.1
this applies only to certain molecules though, it's just a simple way of looking at things
 2 years ago

Omniscience Group TitleBest ResponseYou've already chosen the best response.0
okay i got it. what about molecules is there a legit way?
 2 years ago

Omniscience Group TitleBest ResponseYou've already chosen the best response.0
about other molecules*
 2 years ago

Sheng Group TitleBest ResponseYou've already chosen the best response.1
yes, you have to look at their electronegativity (how much they attract electrons). If there is high electronegativity differences it's most likely a polar bond (e.g. NaCl). But if they got close to no difference (e.g. CH), then it's a nonpolar bond.
 2 years ago

Sheng Group TitleBest ResponseYou've already chosen the best response.1
on top of that, you have to use the 1st rule i mentioned above, a polar bond may be cancelled out by another polar bond on the exact opposite side...e.g. CCl4, even tho the CCl bonds are polar, the exact conformation of the molecule allows all the polarity to cancel out to 0
 2 years ago

Omniscience Group TitleBest ResponseYou've already chosen the best response.0
i got it thanks.
 2 years ago
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