Electronegativty: Nitrogen Vs Chlorine

[ldv1452]

Which is more electronegative, nitrogen or chlorine? Most of what I hear or read says that nitrogen is more electronegative. However, oddly, most electronegativity charts I see show chlorine with a slightly higher value. Why is this?

 

[LogicX]

Which is more electronegative, nitrogen or chlorine? Most of what I hear or read says that nitrogen is more electronegative. However, oddly, most electronegativity charts I see show chlorine with a slightly higher value. Why is this?

My book lists them as the same, 3.0. I think this is because Chlorine is further right on the table, meaning it can hold electrons better from more protons, but is is also bigger, meaning that electrons are held more loosely. Compare this to N, where it is further left, meaning it has a less positive nucleus so it can hold e- as well, but it is also smaller, meaning it can hold them better. This all just happens to work out so that Cl and N have about the same EN when you take all the factors into account.

 

[DrDu]

Trying to try to decide whether chlorine or nitrogen is more electronegative per se is about as academical and useless as discussing how many angels fit on the tip of a needle.
More refined concepts of EN depend on the oxidation state of the atoms, bonding situation and the amount of charge transferred to the bonding partner, so they depend on the kind of bonding one wants to predict!
In school, the use of EN normally only amounts to predicting the polarity of a bond. If you want to know the polarity of an N-Cl bond, simply look it up. That's much more accurate than any prediction based on some crude (and nearly equal) EN scale.

 

[Neon10]

Nitrogen should be more electronegative, because:
1) NCl3 in H2O gives NH3 and HOCl, which proves that nitrogen is negatively charged because it attracts the positively charged hydrogen in H2O to form NH3 and chlorine combines with the negatively charged HO- radicals.
2) HNO3 is stronger that HClO3, though chlorine and nitrogen have the same oxidation state (+5)
pKa HNO3= -1.4
pKa HClO3= -1

3) According to Allen electronegativity scale, nitrogen has 3.07 and chlorine has 2.88

 

[DDTea]

Nitrogen should be more electronegative, because:
1) NCl3 in H2O gives NH3 and HOCl, which proves that nitrogen is negatively charged because it attracts the positively charged hydrogen in H2O to form NH3 and chlorine combines with the negatively charged HO- radicals.
2) HNO3 is stronger that HClO3, though chlorine and nitrogen have the same oxidation state (+5)
pKa HNO3= -1.4
pKa HClO3= -1

3) According to Allen electronegativity scale, nitrogen has 3.07 and chlorine has 2.88

2 and 3 are good explanations, but I'd say #1 is a bit too much of a stretch: you're commenting on a total transformation, which could proceed by many mechanistic steps whose likelihoods are influenced by a lot of variables. Also, everything involved here is electrically neutral; there may be unequal electron sharing in the bonds, but that's not the same as an electrostatic charge. Also, there is no radical chemistry involved here :)

 

[DrDu]

two is also not too convincing as the pKa does not only depend on the bond characteristics but also e.g. on the hydration energy of the nitrate and chlorate ions.