how do you identify the nucleophile? thanks

ah4p

how do i go about working this out?
or do i just need to memorise them

thnks v much for any help :smile:

exam on thursday :frown:

Reply 1

thymolphthalein

A nucleophile by definition is a species with a lone pair of electrons that is used to form a covalent bond with a δ+ atom in another molecule. NH3 has a lone pair. :smile:

Reply 2

urkadee

Also note if there had been an NH2 in the options, the answer would have been NH2, as it has 2 lone pairs of electrons, so it would be more reactive as a nucleophile :smile:

Reply 3

ah4p

Original post by thymolphthalein

A nucleophile by definition is a species with a lone pair of electrons that is used to form a covalent bond with a δ+ atom in another molecule. NH3 has a lone pair. :smile:

Original post by urkadee

Also note if there had been an NH2 in the options, the answer would have been NH2, as it has 2 lone pairs of electrons, so it would be more reactive as a nucleophile :smile:

thank you

but doesnt bromine have three lone pairs around each atom? surely that makes it more nucleophillic?

thnx again

Reply 4

Shannonleah

I need sleep- I read that as "how do you identify as a nucleophile?" 😂

Reply 5

thymolphthalein

Original post by ah4p

thank you

but doesnt bromine have three lone pairs around each atom? surely that makes it more nucleophillic?

thnx again

I guess I wasn't clear enough earlier, sorry. :redface:

Nucleophiles have to be negatively charged ions OR have a strong δ- charge on the molecule (for example, due to the lone pair on NH3).

So although the bromide ion can be a nucleophile, bromine (Br₂) which is given as an option would be incorrect as it is a neutral molecule. It has no significant polarity. :smile:

If I'm being too weirdly unclear about this:
http://www.chemguide.co.uk/mechanisms/nucsub/whatis.html

Chemguide is a pretty neat website. :biggrin:

Reply 6

ah4p

Original post by thymolphthalein

I guess I wasn't clear enough earlier, sorry. :redface:

Nucleophiles have to be negatively charged ions OR have a strong δ- charge on the molecule (for example, due to the lone pair on NH3).

So although the bromide ion can be a nucleophile, bromine (Br₂) which is given as an option would be incorrect as it is a neutral molecule. It has no significant polarity. :smile: