Do alkenes only form carbocations while carbonyl groups only form carbanions?

[brake4country]

Homework Statement

Do alkenes only form carbocations while carbonyl groups only form carbanions?

Homework Equations

NA

The Attempt at a Solution

I understand the relative reactivity of carbocations and carbanions. How does one know when an organic compound follows heterolytic cleavage or homolytic cleavage of H? For example, do alkenes only make carbocations while ketones and aldehydes create carbanions?

 

[Yanick]

You are mixing up quite a few things here and it is very difficult to give you an answer. Let's clear up some terminology and ideas here.

Carbonyl carbons do not form carbanions. In fact, carbonyl carbons have quite a bit of carbocation character, thus they are attacked by nucleophiles (think formation of an amide or any other -COOH type of chemistry).

Homolytic versus heterolytic cleavage does not result in postive versus negative charge. Homolytic cleavage leaves neutral molecules whereas homolytic cleavage will result in one positively and one negatively charged molecule. Please draw these out for yourself.

Please think about some of these ideas/terms and come back with any further questions.