Edexcel a2 chemistry revision for the may/june 2012 exam :)

My chemistry teacher isn't the most reliable source, to be honest, hence why I'm trying to get it confirmed on TSR :P

well I've never seen it on a mark scheme before so I don't think I'm gonna write it

Just revising my transition metal chemistry - can anyone confirm/correct what I understand about why they have coloured ions?

The ligands in the complex ion splits a d orbital (d-d splitting) into two different energy sub levels. The unpaired electron in that orbital absorbs a certain frequency of light and gets promoted to the higher of the two energy sub levels. The electron soon loses the energy gained from the absorption of photons and drops down to the lower energy level of the two sub levels. The process repeats again and again. The colour of the ion that we see is the complementary colour to the frequency of light absorbed by the electron.

Thanks in advance!

I'm going to wait for someone to confirm the bit in bold (or not, as the case may be). Thanks for your help!

What basically happens is that during complex ion formation the d subshell breaks into 2 different energy levels. The light causes the electron to get promoted from a lower d subshell to an upper d subshell. The promotion of the electron causes it to absorb energy from the visible spectrum and the rest of the wavelength is given off as colour.

Hope this helps!

What basically happens is that during complex ion formation the d subshell breaks into 2 different energy levels. The light causes the electron to get promoted from a lower d subshell to an upper d subshell. The promotion of the electron causes it to absorb energy from the visible spectrum and the rest of the wavelength is given off as colour.

Hope this helps!

I wouldn't write down the bit in bold in an exam, it sounds a little like your describing an emission spectrum in that part instead of the absorption spectrum.

Its been a year since i did chem, so i don't remember it now.

I also did the old spec papers, i didn't attempted the questions which aren't related to the new syllabus.

Would someone be able to link me to the old spec papers / markschemes? Thank you

Go to this link.

Can someone tell me the concept behind a buchner funnel ......?! how is the low pressure built up and how is it useful...?

Heeeey is thus for unit 6 chem?
Well... buchner funnel is required when reduced pressure filtration is required... such as for recrystallisation.. we require buchner funnel..during recrystallisation the buchner runner would be able to suck out the mother liquor.. this is due to the low pressure..the low pressure is built up due to the presence of a vacuum pump which sucks out the air...take it as a suction pump you see at the dentist when they put it in your mouth..its able to suck out the liquid.

Those of you who are studying from George Facer sill you be studying the edexcel textbook as well?

Yes I tend to use both in combination. I also have the CGP A2 revision guide and these revision guides for unit 4 and 5, also by George Facer. Getting your information from a range of revision sources definitely helps me, and I also find that there are areas that are better explained in one book compared to another. For example I find the further organic chemistry (unit 4) in the Edexcel textbook better than the Facer book, but the transition metal chemistry (unit 5) in the Facer book better than the Edexcel book!

Yes I tend to use both in combination. I also have the CGP A2 revision guide and these revision guides for unit 4 and 5, also by George Facer. Getting your information from a range of revision sources definitely helps me, and I also find that there are areas that are better explained in one book compared to another. For example I find the further organic chemistry (unit 4) in the Edexcel textbook better than the Facer book, but the transition metal chemistry (unit 5) in the Facer book better than the Edexcel book!

heey can you give me the list of topics which are better explained in the edexcel textbook than the facer book please ??