[wam-bam]

why doesn't [Zn(NH3)6]4+ ever form

[NutterFrutter]

(Original post by wam-bam)
why doesn't [Zn(NH3)6]4+ ever form

NH3 has no overall a charge, the only ion of Zinc is a 2+ ion, so this 4+ complex could never form as Zn^4+ doesn't exist.

[wam-bam]

(Original post by NutterFrutter)
NH3 has no overall a charge, the only ion of Zinc is a 2+ ion, so this 4+ complex could never form as Zn^4+ doesn't exist.

okay so my question is more why can't Zn form 6 ligands with NH3 but it can form [Zn(NH3)4(H2O)2] happily??

[aqua05]

guys i feel so scared & nervous for unit 5 chem
I really cant understand it.... any suggestions or tips on how to go about it ?

[NutterFrutter]

(Original post by aqua05)
guys i feel so scared & nervous for unit 5 chem
I really cant understand it.... any suggestions or tips on how to go about it ?

What don't you understand? The difficulty of the unit 5 content is about the same as unit 4, there is just quite a bit more to learn.

[aqua05]

(Original post by NutterFrutter)
What don't you understand? The difficulty of the unit 5 content is about the same as unit 4, there is just quite a bit more to learn.

I really dont know
I was just going through & i feel really lost... how do you study chem ?

[NutterFrutter]

(Original post by aqua05)
I really dont know
I was just going through & i feel really lost... how do you study chem ?

Colourful notes, lots of past paper questions.

[aqua05]

(Original post by NutterFrutter)
Colourful notes, lots of past paper questions.

You studying the old syllabus papers as well ?
Are there chem salters nuffield papers ? Just wondering
What resources are you using to study ?

I;m so sorry for asking you so many questions... its just that i'm really tensed

[This Honest]

(Original post by aqua05)
You studying the old syllabus papers as well ?
Are there chem salters nuffield papers ? Just wondering
What resources are you using to study ?

I;m so sorry for asking you so many questions... its just that i'm really tensed

I'm going to start doing the salters nufffield papers during holidays. Then official edexcel in early mayish.
facer book is alright but it gets confusing at times.
Look at your syllabus and tick off what you know and don't know. That'll make it easier for you. (I need to do this at some point too )

[aqua05]

Hello,
Can someone help me how to write the formula for complex ions ?
I have forgotten :/
For instance if we are given the metal cation Fe3+, ligand(CN-) & co-ordination number (6)...how do we get the formula as [Fe(CN)6]4-

[Cyber123]

(Original post by raheem94)
I agree with you, the edexcel text book isn't any good.

George facer is the best.

I don't know about any revision guides, i didn't used those things. But i do advice to do a lot of past papers, even the old ones. Don't do the questions(in the old past papers) which are not in the spec, if you are not sure which type of questions aren't in the new spec then ask your teacher.

Also use the mark scheme a lot for chemistry, i will advice you to learn the definitions and details about reactions, like conditions etc from the mark scheme. Books don't always give the same conditions for reactions, they differ, so it will be best to use the mark scheme to ensure that what you are learning is correct.

Also don't take A2 chemistry as easy as AS chemistry, A2 is much harder than AS.

By the way, i am not taking any exams in chemistry. I did edexcel chemistry last year, achieved an A* (AS: 300/300 A2 272/300).

Best of luck for your exams

Heyyy, congratulations on your A* you must be a genius. Would you recommend the cgp book because I am not sure whether or not I should buy it. Also did you revise using flashcards and that sort.
Thanks

[raheem94]

(Original post by Cyber123)
Heyyy, congratulations on your A* you must be a genius. Would you recommend the cgp book because I am not sure whether or not I should buy it. Also did you revise using flashcards and that sort.
Thanks

Thanks, but i am not a genius. Getting an A* is not a very big deal.

I didn't used any of those, cgp book and flashcards.

I don't have any idea about the cgp book, i have never seen it.

I did a lot of past papers, of the complete decade. Actually i don't like chemistry very much, i like maths, so it was tough for me to concentrate on chemistry. But in the end when the exam neared then i got serious about chemistry and studied everything then practiced a decade of past papers. So as i did the past papers late, hence i didn't needed to do any revision, as everything was in my mind.

[NutterFrutter]

(Original post by aqua05)
Hello,
Can someone help me how to write the formula for complex ions ?
I have forgotten :/
For instance if we are given the metal cation Fe3+, ligand(CN-) & co-ordination number (6)...how do we get the formula as [Fe(CN)6]4-

Surely, it'd be [Fe(CN)6]3-

The coordination number tells you the number of dative covalent bonds that form, in this case you know there are 6 dative covalent bonds and so you will have 6 ligands of CN- (remember CN- is monodentate).

Put it all together and you get [Fe(CN)6]3-, the overall charge is 3- because +3 + (-6) = -3.

[aqua05]

(Original post by NutterFrutter)
Surely, it'd be [Fe(CN)6]3-

The coordination number tells you the number of dative covalent bonds that form, in this case you know there are 6 dative covalent bonds and so you will have 6 ligands of CN- (remember CN- is monodentate).

Put it all together and you get [Fe(CN)6]3-, the overall charge is 3- because +3 + (-6) = -3.

why did you put a -ve sign around the 6 when calculating the overall charge ?

[NutterFrutter]

(Original post by aqua05)
why did you put a -ve sign around the 6 when calculating the overall charge ?

The Cyano group is CN-.

[aqua05]

(Original post by NutterFrutter)
The Cyano group is CN-.

aaaaww...thankss

[aqua05]

can someone please help me out with the transition element bit.. the place where they form complex ions & stuff...its so mega confusing!

[NutterFrutter]

(Original post by aqua05)
can someone please help me out with the transition element bit.. the place where they form complex ions & stuff...its so mega confusing!

Need more details...

[aqua05]

heey...can someone please help me with calculating the errors...as in when are we suppose to multiply by 2?
I need help in apparatus such as burette, pipette, thermometer and balance...
Thank you

[aqua05]

(Original post by NutterFrutter)
Need more details...

oh gosh! i just read this post... i solved my problems with my teacher.. im okay with it
Thanksssss