AQA AS Chemistry, unit 1

Reply 40

x-Sophie-x

13

Original post by Sharif Chowdhury

Omg, I didn't even realise you could do that, I feel silly now... haha, you learn something new every day.

Indeed you do :biggrin:

Reply 41

username984585

20

Original post by Chewy29

Has graphene appeared on the spec and if it has what the hell is it?

Posted from TSR Mobile

Its basically like graphite. It came up on the June 2012 paper.

Reply 42

studentindistres

I always trip up on the deduce this isotope question, help/:

Reply 43

NabRoh

11

Original post by Sharif Chowdhury

Here's a picture illustrating the order in which electron subshells fill. Sorry for my bad paint skills xD
Learn how to draw this diagram and you'll never forget the order of subshells.

Original post by x-Sophie-x

5s2 4d10 5p1

There aren't f blocks yet. At least thats what I think :smile:

Cheers all! I think I've got it down. :smile:

Reply 44

gooner1886

Original post by studentindistres

I always trip up on the deduce this isotope question, help/:

Post up the question :smile:

Reply 45

gooner1886

Original post by NabRoh

Could someone explain to me how shells are filled up using Indium as an example?
Does the 4th shell have an f block (14?)?

So if we went up to the 6th shell would it be:

1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 ...

What comes next?

I just remember the following:
1s
2s 2p
3s 3p
4s 3d 4p
5s 4d 5p
6s 4f 5d 6p

It makes a sort of L shape :wink:

2 electrons in S
6 in P
10 in D
14 in F

Reply 46

a.jiwa

Hello fellow unit 1ers

Does anyone know an easy way to remember the shapes of molecules both with lone pairs and bond angles and stuff?? I always memorize them and forget them like a week later its really annoying :unimpressed:

Posted from TSR Mobile

Reply 47

sofiamalik_1995

Original post by mattj94

I have created revision notes for this exam and they can be found on my website http://www.mattsrevision.com/chemistry-in-action/

Matt

Thanks for the notes Matt :smile:

Reply 48

sofiamalik_1995

Original post by NabRoh

Could someone explain to me how shells are filled up using Indium as an example?
Does the 4th shell have an f block (14?)?

So if we went up to the 6th shell would it be:

1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 ...

What comes next?

Not 100% sure if this is right...

1s² 2s² 2p⁶ 3s² 3p⁶4s² 3d¹⁰ 4p⁶ 5s² (orbitals with a higher energy are filled first)

Please correct me if i am wrong :smile:

also yes the 4th shell has an f orbital.... apply the formula 2(n^2)
2(n^2)= 2(4^2)= 32 electrons in the 4th shell
1 4s orbital + 1 4p orbital + 1 4d orbital + 1 4f orbital= 32 atomic orbitals

Reply 49

Paulineuh

Original post by a.jiwa

Hello fellow unit 1ers

Does anyone know an easy way to remember the shapes of molecules both with lone pairs and bond angles and stuff?? I always memorize them and forget them like a week later its really annoying :unimpressed:

Posted from TSR Mobile

I found it helpful creating a table like the one in Matt's revision notes (http://www.mattsrevision.com/chemistry-in-action/), I don't know I just find it more useful :biggrin:

It sticks more because when I try and remember it again, I just think of the order I put the info in on the table!

Reply 50

a.jiwa

Original post by Paulineuh

I found it helpful creating a table like the one in Matt's revision notes (http://www.mattsrevision.com/chemistry-in-action/), I don't know I just find it more useful :biggrin:

It sticks more because when I try and remember it again, I just think of the order I put the info in on the table!

Thanks for that! ! I'll have a go hope it works! :yy:

Reply 51

NabRoh

11

Original post by sofiamalik_1995

Not 100% sure if this is right...

1s² 2s² 2p⁶ 3s² 3p⁶4s² 3d¹⁰ 4p⁶ 5s² (orbitals with a higher energy are filled first)

Please correct me if i am wrong :smile:

also yes the 4th shell has an f orbital.... apply the formula 2(n^2)
2(n^2)= 2(4^2)= 32 electrons in the 4th shell
1 4s orbital + 1 4p orbital + 1 4d orbital + 1 4f orbital= 32 atomic orbitals

So there is a 4f orbital? This goes against what everyone else said... :s-smilie:

Reply 52

NabRoh

11

Original post by sofiamalik_1995

.

Original post by gooner1886

.

Original post by x-Sophie-x

No F orbitals yet.
We dont need to know about f orbitals in unit 1 chemistry :tongue:

Original post by Sharif Chowdhury

.

According to the mark scheme, no f orbitals... :rolleyes:

Reply 53

maryamnc

2

Original post by x-Sophie-x

I'm taking this exam for the first time. Because our stupid school insists we get better results if we do both units in the summer Urgh! :angry:

I hate periodicity the most :frown:

Posted from TSR Mobile

Exactly the same! And then I end up with 8 units in june so it's harder! :angry:

Reply 54

homefind

Original post by Chewy29

Has graphene appeared on the spec and if it has what the hell is it?

Posted from TSR Mobile

It's not on the spec, but I think it has come up in the past but as an application type question as it is similar to graphite

Posted from TSR Mobile

Reply 55

a.jiwa

people,
for AS AQA do we need to know about the anomalous electron configurations of chromium and copper?

I just had a read through the old text book and it does mention it there but im not sure if its on specification or if aqa will decide to be nasty and throw it in the exam?

The text book says :
Copper and chromium electron configurations do not follow the pattern and are anomalous:

- Chromium is 1s2 2s2 2p6 3s2 3p6 4s1 3d5
NOT 1s2 2s2 2p6 3s2 3p6 4s2 3d4

- copper is 1s2 2s2 2p6 3s2 3p6 4s1 3d10
NOT 1s2 2s2 2p6 3s2 3p6 4s2 3d9

The explanation of this which i didnt fully understand according to ye olde text book is:
The reason for these anomoules is that both cases the outer sub levels are either full or half full and the structures shown are of lower energy and represent more stable arrangements..

has ANYONE seen this come up in a past paper?

Reply 56

Paulineuh

Original post by a.jiwa

people,
for AS AQA do we need to know about the anomalous electron configurations of chromium and copper?

I just had a read through the old text book and it does mention it there but im not sure if its on specification or if aqa will decide to be nasty and throw it in the exam?

The text book says :
Copper and chromium electron configurations do not follow the pattern and are anomalous:

- Chromium is 1s2 2s2 2p6 3s2 3p6 4s1 3d5
NOT 1s2 2s2 2p6 3s2 3p6 4s2 3d4

- copper is 1s2 2s2 2p6 3s2 3p6 4s1 3d10
NOT 1s2 2s2 2p6 3s2 3p6 4s2 3d9

The explanation of this which i didnt fully understand according to ye olde text book is:
The reason for these anomoules is that both cases the outer sub levels are either full or half full and the structures shown are of lower energy and represent more stable arrangements..

has ANYONE seen this come up in a past paper?

I personally haven't seen it on a past paper and I've done nearly all from 2002 and 2006-2013 :s-smilie:

I've just been looking at the spec and it doesn't show anything about knowing the copper and chromium specifically :smile:

Hopefully AQA won't throw that in tomorrow's exam :frown:

The explanation doesn't really make sense to me lol

Reply 57

Tabby.1.2

please can someone explain this to me, i think i'm having a blonde moment ?!
i was doing a past paper and i cannot work out this 1 mark question hahah :

Norgessaltpeter was the first nitrogen fertiliser to be manufactured in Norway.
It has the formula Ca(NO3)2
Norgessaltpeter can be made by the reaction of calcium carbonate with
dilute nitric acid as shown by the following equation.

CaCO3(s) + 2HNO3(aq) Ca(NO3)2(aq) + CO2(g) + H2O(I)

In an experiment, an excess of powdered calcium carbonate was added to 36.2 cm3
of 0.586 mol dm–3 nitric acid.

Calculate the amount, in moles, of HNO3 in 36.2 cm3 of 0.586 mol dm–3 nitric acid.
Give your answer to 3 significant figures.

Reply 58

a.jiwa

Original post by Paulineuh

I personally haven't seen it on a past paper and I've done nearly all from 2002 and 2006-2013 :s-smilie:

I've just been looking at the spec and it doesn't show anything about knowing the copper and chromium specifically :smile:

Hopefully AQA won't throw that in tomorrow's exam :frown:

The explanation doesn't really make sense to me lol

Yeahhh i dont remember seeing it anywhere and hopefully they dont thorw it in! i think ill probably have memorized the explanation just to be safe however if they ask me to apply it i have no idea what the explanation actually means either :confused: