~The Council Of Youngers of BYC! (COY)~

Date sort Score sort
No-one is online *tears roll down face*
I will scroll through the properties of elements all by my lonesome. I will note my findings here (digging through this lecturer's notes seriously warrants a colossal effort) because I can't be bothered writing - I have this paper cut on the inside of my thumb. How. Why. :P

Group 1 and 2
Reactivity of Compounds:
  • Group 14-15: Metal replaced with H upon reaction with water or acid
  • Group 16-17: Metal and non-metal ions into solution (with the exception of oxygen - hydroxide). No acids formed as they would be stronger acids than water. The only way I can attempt to visualise this is that H+ drops back off the acid rather than leaving the water to form the acid... wth

Group 13
  • Good Lewis acids because they have free p orbitals.
  • Diborane not electron deficient under MO theory
  • BF3 is a monomer because fluorine is electronegative and stabilises the molecule. The hydrogens in BH3 can't do that so electrons need to be shared from a B-H bond in another molecule.

Compounds:

  • BN, AlN isoelectronic with carbon. Similar properties.
  • BCl3 and Al2Cl6 because of relative sizes of metals. (I always used to think that was the argument for borane vs BF3... I must've lost at least 1% of my grade just because of that stupid question continually coming up. :P)
  • Lewis acid-base reaction comes from a bond forming between HOMO on the base and LUMO on the acid. (Yeah I know, weird names - when I first heard them in class I hadn't been paying attention and I was like, what on earth is he rabbiting on about. They stand for highest occupied molecular orbital and lowest occupied MO.)

Group 14
Dude seriously?! "Carbon and Silicon - life and death"?! Don't be mean to rocks. Rocks are awesome.

...But yeah, they are pretty dead lol.

  • Tetrahedral covalent networks - hard materials
  • H-O bonds are strong (I'm assuming because group 14's not very electronegative so OH is allowed to keep its electron in peace) so oxo-acids are weak.

Group 15

Acids:
  • Why H3PO3 can only donate 2 protons whereas H3PO4 can donate 3 : only H attached to oxygen are acidic.
  • Why H3PO3 is weaker than H3PO4 : there are fewer oxygens so the O-H bonds are stronger. Less oxygens to pull electron density away from hydrogen.

Group 16

Reactivity of Oxygen
  • O2 reactive because it has unpaired electrons in MO theory.
  • Similar sized atoms = good overlap with other period 2 elements' orbitals so pi bonds (double and triple bonds) form.

Oxides

  • SiO2 - four bridging oxygens
  • P2O5 - three bridging, one terminal
  • SO3 - two bridging, two terminal. trimer or long chain.
  • Cl2O7 - one bridging, three terminal.

Woohee! I've just discovered group 17 isn't even covered in the exam. Fantastic.

So good. The last slide of the notes says:
And that’s all
Thanks to our life supporters H, C, N, O, and P
and minor sponsors Groups 1 and 2 and the transition elements



And if all else fails... remember that everything occurs because it's energetically favourable. :P
 
Last edited:
Ich bin jetzt ganz fertig! :yesss: Das war die letzte, die ich gar nicht verstehen habe. Alles gut für Prufung am Montag. Spaß Spaß Spaß.
 
1 down 3 to go. Sounds much better than 1 down 14 to go. University 1, school 0. :P

wasn't difficult which the past papers were suggesting would be the case. now I hope I don't get like 70% because that would just be awkward.
 
Fierlin1182 said:
1 down 3 to go. Sounds much better than 1 down 14 to go. University 1, school 0.
tongue.png


wasn't difficult which the past papers were suggesting would be the case. now I hope I don't get like 70% because that would just be awkward.
Click to expand...
clap.gif
I'm sure you'll do fine.
 

New posts New threads Active threads

Back
Top Bottom