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Source of electrons

Posted: Sat Feb 27, 2016 2:38 pm
by 204635822
How do I know whether the source of the electrons is the bond or the atom when drawing arrows

Re: Source of electrons

Posted: Sat Feb 27, 2016 2:51 pm
by AuraCruzHeredia_1L
Can you provide an example? I'm not quite sure what you're asking.

I think maybe you're questioning if the e- source is say a double bond or a Cl with 3 lone pairs (maybe something like H2C=CHCl)?

In this case, you'd just pay attention to electronegativities (how hard will it be to take away electrons).

Since Cl is more electronegative than C, then it'll be easier to take away electrons from C
(ie. from the double bond) than from Cl because Cl holds onto them tightly.


If your question is just about how we draw the arrows, then you always draw them from where they're leaving to where they're going. So the arrow head points at the E+ (electrophile) and the arrow's tail should be rooted at the Nucleophile (Nu-).

Idk, let me know if this helps/you have a more specific question/example. Hope it helps.

Re: Source of electrons

Posted: Sat Feb 27, 2016 11:39 pm
by JudithGonzalez_1G
Most of the time if the electrons are coming from a bond it is from a double bond that is breaking or a single bond that is breaking and is giving it's electrons to to fill another atom, like H-O breaking and Hydrogen giving the two electrons from the bond to fill Oxygen's octet. The source of electrons is from the atom when that atom is attaching to a delta positive atom, such as the H+ from the breaking of H-O attaching to a Carbon atom.