Resonance stability question

[dentspade]

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Can someone tell me if I am on the right track or not..

In regards to inductive effects, since a carbocation is already electron deficient, when an electron withdrawing group pulls on it, the carbocation becomes MORE POSITIVE, therefore LESS STABLE?
And since a carbanion has too many electrons, when an electron withdrawing group pulls on it, it becomes MORE POSITIVE and MORE STABLE?

I just finished watching Chad's resonance video for orgo and this is where I got that from.

 

[averageasian]

to #1, yes! and for #2, i want to say yes as well. Remember your trends for anion (1>2>3) and cation (3>2>1) stability.

 

[dentspade]

to #1, yes! and for #2, i want to say yes as well. Remember your trends for anion (1>2>3) and cation (3>2>1) stability.

I guess what I'm more confused as to what I wrote down in my notes..

Carbocation stability 3>2>1>Me; 3 is more stable than 2>1>Me because it is stabilized by resonance and inductive effects. It has three neighbors that can donate electrons to him, therefore making him more stable (less reactive). Does the donation of protons from his neighbors make him more negative or more positive? If more negative, I thought the more negative, the less stable, the more reactive.

Carbanion stability Me>1>2>3; 3 is less stable than because he has too many electrons, so the donation of electrons from his neighbors make him more negative, less stable.

Maybe I just wrote things wrong down in my notes??

 

[dentspade]

So I know more stable always = less reactive = lower energy, and less stable always = more reactive = higher energy. But where does more negative/more positive come into play here

 

[averageasian]

for a tertiary cation, I have always though of the methyl groups being the e- donating groups. Since a cation is positive, the 3 methyl groups dump in e density to offset it. So it makes the cation less positive, more negative as a result. Bc you offset the positivity, you stabilize it.

and for the carbanion thing, sounds correct to me

 

[averageasian]

Negative positive relate to stability to the trends your already know (3,2,1 etc). How well you can BALANCE these out determines stability. A tertiary cation is well balanced due to 3, e- donating groups present. and so forth

 

[Cool Beans]

Species tend to be more stable when they are neutral as compared to when they are charged (either positive or negative). I think if you just tweek how you originally stated it just a little bit it would make more sense. An electron-withdrawing group makes a carbocation less stable because it makes it more positive (further from neutral), whereas an electron-withdrawing group makes a carbanion more stable because it makes it LESS NEGATIVE (closer to neutral). You said an electron-withdrawing group makes a carbanion more positive rather than less negative which is ultimately the same thing and technically correct but is potentially confusing.
Hope this helps!