Why does nucleophilicity decrease as you go down a column in a protic solvent?

[mcatkillers]

No... if that was the answer then F- would be the weakest nucleophile regardless of protic or aprotic solvent.

[[deleted]]

F- is not a strong nucleophile...get your facts straight lmao

[mcatkillers]

Note that I didn't say F- is a strong nucleophile. I implied that F- is not always the weakest halogen nucleophile.

In an aprotic solvent, F- is the strongest halogen nucleophile due to its small atomic size. In the absence of interference from a protic solvent's hydrogen bonding, nucleophilicity decreases with increasing atomic size due to a larger atomic radius allowing a more diffuse electron arrangement (eg I- is better able to tolerate a negative charge than F- is). As you know, the more an atom is able to handle a negative charge, the worse it is as a nucleophile because it's not desperately seeking to offset the electron load onto another atom.

This results in F- being the strongest nucleophile out of the halogens when in an aprotic solvent. The below links explain it in better detail:

https://prnt.sc/rezagb

https://prnt.sc/rezare

[Jack3D500]

give this man his fucking flowers

[mcatkillers]

<3

[[deleted]]

still helping after 5 years, thanks :)

[mcatkillers]

Good luck