Ocr f321 23 may 2013~official discussion thread

Scroll to see replies

Another question how do we know the difference between giant covalent and simple molecular for e.g. SiCl4 and SiO2? :s-smilie:

On the official OCR textbook on page 87 it will show you how. Its where the element is positioned on the periodic table.

Reply 501

anonymousecheese

Original post by Ché.

Sure!
Right, so?
Automatically, you would reference to Group Three considering the part "third"...
We would then take the word "smallest" and it should trigger that it could be Boron as it will have less electron shielding have more of a strong nuclear attraction.

So, once again referring to the term "the first twenty", Aluminium is spot on!

:biggrin:

Clear?

Posted from TSR Mobile

I GET IT

oops just saw the next quwstion- dont get it
the biggest change in the I.E. 's is between the 2nd and 3rd IE
therefore doesnt it mean the the element should have 4 outer shell electrons and therefore be in group 4.

(edited 10 years ago)

Reply 502

SchoolKid.

Can someone help me with this killer question q3di -

http://www.ocr.org.uk/Images/61532-question-paper-unit-f321-atoms-bonds-and-groups.pdf

http://www.ocr.org.uk/Images/65127-mark-scheme-unit-f321-atoms-bonds-and-groups-june.pdf

Spent half an hour on this question and I just dont get it. Any help would be great.

(edited 10 years ago)

Reply 503

Ché.

Original post by Kitnimohabbathai

guys whats the difference between si02 and sicl4? how do you work out what type of structure/bonding they have? I thought si02 would have permanent dipole-dipole? aren't they both covalent and simple molecular? is the difference that si02 is giant covalent but sicl4 isn't?

SiCl4 - The charges all cancel out and form symmetrical shape.
Thus, the molecule now simply...no lone pairs, no nothing.
So, it'll obtain Van der Waals - as do most - and go from there!

SiO2 - It'll have two bonding and lone pairs.
Thus, it will be covalently bonded.
This content isn't directly in the mark scheme but it helps discover the structures!

:wink:

.

Posted from TSR Mobile

Reply 504

Legal drugdealer

Original post by SchoolKid.

Can someone help me with this killer question q4di -

http://www.ocr.org.uk/Images/61532-question-paper-unit-f321-atoms-bonds-and-groups.pdf

http://www.ocr.org.uk/Images/65127-mark-scheme-unit-f321-atoms-bonds-and-groups-june.pdf

Spent half an hour on this question and I just dont get it. Any help would be great.

do you mean ci

Reply 505

General SMG

Original post by SchoolKid.

there is no Q4d(i)

Reply 506

Ché.

Original post by SchoolKid.

Is there a Question 4di) in this paper!?

Posted from TSR Mobile

Reply 507

SchoolKid.

Original post by Legal drugdealer

do you mean ci

Sorry I mean Q3di

Reply 508

Kitnimohabbathai

Original post by General SMG

there is no Q4d(i)

I think they mean 3di the one on ionisation energies...you basically write out the electron configuration for aluminium...1s2,2s2,2p6,3s2,3p1...so the 1st is p...2nd and 3rd are S....

Reply 509

General SMG

Original post by SchoolKid.

Sorry I mean Q3di

oo, I remember doing this question a little while ago, you have to look at the electron configuration of Al

Reply 510

Legal drugdealer

Original post by SchoolKid.

Sorry I mean Q3di

Write out the electron config of aluminum actually that's a better way.

(edited 10 years ago)

Reply 511

Ché.

Original post by SchoolKid.

Sorry I mean Q3di

ANSWER:
2nd, 3rd, 10th and 11th!

STRATEGY:
Write the electron configuration backwards per electron removal for all what you are given in a question..
Wherever the s-orbitals are, in this context, you'll get it!

Posted from TSR Mobile

(edited 10 years ago)

Reply 512

Kitnimohabbathai

Original post by Ché.

ANSWER:
2nd and 3rd!

STRATEGY:
Write the electron configuration backwards per electron removal for all what you are given in a question..
Wherever the s-orbitals are, in this context, you'll get it!

Posted from TSR Mobile

you're really good at explaining answers :wink:

Reply 513

Kitnimohabbathai

hey have you guys done all the papers....I still have 2012 and 2013 left :/ did them ages ago..should I do them again now or just look through them?

Reply 514

SchoolKid.

Original post by Kitnimohabbathai

I think they mean 3di the one on ionisation energies...you basically write out the electron configuration for aluminium...1s2,2s2,2p6,3s2,3p1...so the 1st is p...2nd and 3rd are S....

Original post by General SMG

oo, I remember doing this question a little while ago, you have to look at the electron configuration of Al

Original post by Legal drugdealer

Write out the electron config of aluminum actually that's a better way.

Original post by Ché.

Thank you ALL SOOO MUCH! I get it know...finally :smile:

Reply 515

Ché.

Original post by Kitnimohabbathai

you're really good at explaining answers :wink:

Ah!
Am I?
Thank you very much; I really don't want to give badly explained answers for everyone to become distressed and all!
I am glad I can give the right answers!

How's everyone feeling overall for tomorrow?

Posted from TSR Mobile

Reply 516

Kitnimohabbathai

Original post by Ché.

hey have you guys done all the papers....I still have 2012 and 2013 left :/ did them ages ago..should I do them again now or just look through them?

Reply 517

Ché.

Original post by Kitnimohabbathai

hey have you guys done all the papers....I still have 2012 and 2013 left :/ did them ages ago..should I do them again now or just look through them?

Don't put yourself under TOO much pressure in this instance!

I would advise that you go through the questions and you'll gain a feel for nay new ways they ask questions which are stuff we really know!
Reports help a little... You'll see how the commentary on how questions go; harder ones won't change but easier answers might incorporate that one mark MORE!

You never know...
Good luck!
:biggrin:

Posted from TSR Mobile

Reply 518

anonymousecheese