electronegativity difference

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sarahtang4B
Posts: 132
Joined: Fri Sep 28, 2018 12:27 am

electronegativity difference

Postby sarahtang4B » Sun Nov 04, 2018 9:47 pm

on homework question 2.d.5 it asks if CO2 or CS2 is more covalent and on the periodic table these elements are all relatively close to each other so how we we know which is more ionic without being given a chart with their electronegativities?

405112316
Posts: 62
Joined: Fri Sep 28, 2018 12:17 am

Re: electronegativity difference

Postby 405112316 » Sun Nov 04, 2018 10:01 pm

If you look at a periodic table that includes electronegativity of atoms, you can calculate the electronegativity difference between the 2 bonding atoms and determine which molecule is more electronegative.
C - 2.55
S - 2.58
O - 3.44

There is a greater difference between C and O, making CO2 more electronegative.

Tessa Lawler 1A
Posts: 57
Joined: Fri Sep 28, 2018 12:18 am

Re: electronegativity difference

Postby Tessa Lawler 1A » Sun Nov 04, 2018 11:49 pm

This is kind of a tricky one. In determining which molecule is more covalent, you do want to look to electronegativity, but almost more importantly, you want to look to the proximity of the atoms in the molecule. The closer the electronegativity values of the atoms in the molecule are to one another, the more covalent the molecule's bonds will be. We can say that C and O are only two elements apart, but C and S are three. Since C and O are closer together and share closer values of electronegativity, I would say that their molecule is the most covalent.
It doesn't necessarily have to do with how electronegative the atoms are, but rather how electronegative they are to one another.

Roberto Gonzalez 1L
Posts: 39
Joined: Fri Sep 28, 2018 12:17 am

Re: electronegativity difference

Postby Roberto Gonzalez 1L » Sun Nov 04, 2018 11:52 pm

If the difference in electronegativity of a molecule falls between 2 and 1.5 would it be necessary to classify said bond as a covalent bond with ionic characteristics or would it simply be a covalent bond?

megan blatt 2B
Posts: 61
Joined: Fri Sep 28, 2018 12:28 am

Re: electronegativity difference

Postby megan blatt 2B » Tue Nov 06, 2018 10:35 am

I believe that if the electronegativity difference falls between 1.5 and 2, that it is a case by case basis. I think that depending on which types of elements are involved in the bond (metal, metalloid, nonmetal) you can determine whether it is ionic or covalent. If it is covalent, it will very likely be polar given that it is pretty close to becoming ionic. In fact, whenever there is a bond that is between two different elements, there will be some form of polarity or uneven distribution of electron density even if it is so small that it can not be easily detected.


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