Electron Donating and Withdrawing groups question

[Claritynow]

As I am going over all the Organic Chemistry content I have come across Electron donating and withdrawing groups. I have seen them mostly in the scope of the benzene ring and whether they will be activating or donating in terms of the ring.

My question is that is it fruitful to memorize which groups are donating or which groups are withdrawing? I am trying to maximize the tudying time by looking at the functional groups and how they operate. Any advice or help will be greatly appreciated. Thank you. And good luck to everyone studying for the exam/

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[Amba]

Attempt to understand WHY they donate or withdraw and it's easy. Find common patterns. I'd give some examples but I've forgotten most of that since I'm done with the MCAT.

 

[BerkReviewTeach]

My question is that is it fruitful to memorize which groups are donating or which groups are withdrawing?

No for a couple reasons. First, there is a simple way to determine which are EWGs and which are EDGs by looking for lone pairs and pi-bonds. Second, benzene chemistry (activation and deactivation included) is NOT tested on the MCAT. I think the second reason is the better one.

They could ask about how EDGs and EWGs affect acidity and basicity, so the fundamental concept might be good to know. But don't study benzene chemistry. Print out the AAMC list of topics (30 pages maybe?) and only study topics from that list.

 

[ridethecliche]

The extreme ones come down to electronegativity.

Having a nitro group on something is a whole lotta EN right there. If it's not going to withdraw electrons like woah, then it's probably having a crisis of faith. Or is, you know, bipolar.

PUN!

 

[shoehornlettuce]

There really isn't much to memorize. Just remember 3 things.

-halogens are in a group by themselves and deactivate the ring.

-Any atom that is bonded directly to the benzene ring and has another more electronegative atom bonded to it is electron withdrawing. For example, say the ring has a carboxylic acid on it. The carbon of the carboxylic acid is bonded to the ring and oxygen is in turn bonded to the carbon. Oxygen is more electronegative than the carbon so COOH deactivates the ring. It's pulling electron density away.

-Any atom that is bonded directly to the benzene ring and has another less electronegative atom bonded to it is electron donating. For example, say the ring has NH2 on it. The nitrogen is bonded directly to the ring and the hydrogens are less electronegative than the nitrogen so NH2 activates the ring. The loan pair on the nitrogen can go into the ring because there is nothing more electronegative on the other side trying to hog the electrons.

 

[O-Block Uchiha]

There really isn't much to memorize. Just remember 3 things.

-halogens are in a group by themselves and deactivate the ring.

-Any atom that is bonded directly to the benzene ring and has another more electronegative atom bonded to it is electron withdrawing. For example, say the ring has a carboxylic acid on it. The carbon of the carboxylic acid is bonded to the ring and oxygen is in turn bonded to the carbon. Oxygen is more electronegative than the carbon so COOH deactivates the ring. It's pulling electron density away.

-Any atom that is bonded directly to the benzene ring and has another less electronegative atom bonded to it is electron donating. For example, say the ring has NH2 on it. The nitrogen is bonded directly to the ring and the hydrogens are less electronegative than the nitrogen so NH2 activates the ring. The loan pair on the nitrogen can go into the ring because there is nothing more electronegative on the other side trying to hog the electrons.

this right here was a perfect explanation, thank you lol

 

[aldol16]

You shouldn't be dedicating computational space in your head to memorizing anything really but the amino acids. You should understand why certain things are electron-withdrawing or electron-donating. You will be asked to use your critical reasoning skills on the MCAT and a question could very well ask you about relative acidities or basicities. These properties have a lot to do with EWGs and EDGs.