How do I find the most basic atom (most likely to accept H+) in a molecule?

Question

anonymous · Answer

There are two OH groups and a NH2 group...

rushwr · Answer

To accept H+ (protons)  The basic atom should have lone pairs :)

anonymous · Answer

Thanks! All three possibilities have lone pairs. One lone pair on the N and 2 lone pairs on the O

rushwr · Answer

@taramgrant0543664

taramgrant0543664 · Answer

It depends on the acidity and basicity of the lone pairs

rushwr · Answer

that's how I thought  too !

taramgrant0543664 · Answer

The one that is more basic is the one that H+ will attach to

photon336 · Answer

This is a question of Basicity; which one is most likely to accept an H+ means the element that is more likely to donate it's a pair of electrons. 

for this I relate this concept to how nucleophilic the element is, meaning it's tendency to donate a pair of electrons. 

Oxygen and Nitrogen; oxygen is more electronegative that nitrogen, meaning that it's  less likely to donate electrons. Nitrogen; is less electronegative more likely to give up a pair of electrons and accept an H+ 

I would say it's the nitrogen

rushwr · Answer

@taramgrant0543664  But I thought in the way orgoldfish thought. Cuz when u have more lone pairs the ability to attract protons is high. Thus the basicity increases due to the attraction of higher number of H+

photon336 · Answer

I feel that the molecule needs to be more likely to give up it's electrons and take on a proton. 

if something is acidic then it's more likely that it's going to give up a proton, and it's conjugate base is going to be stable, that atom must be able to stabilize the negative charge well other wise it wouldn't want to lose the proton.

taramgrant0543664 · Answer

The lone pair on the neutral N in the NH3 is more stable than the anionic lone pair on O in OH.  Therefore, the lone pair on NH3 is less basic. 
The conjugate acid of OH is water which has a pKa = 15.7.  The conjugate acid of NH3 is NH4+ which has a pKa = 9.  Therefore, NH3 has the more acidic conjugate acid and is the weaker base.
Basic atoms in a molecule will have lone pairs, to accept the proton(s). So I'm thinking oxygen

welshfella · Answer

I agree with taramgrant

photon336 · Answer

@abb0t thoughts?

abb0t · Answer

Perhaps an example might help?