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# AS Chemistry- helping each other out! watch

1. (Original post by Dyl98an)
No in general. Because sometimes the 3d orbital comes after. How would you know when to write 3d after 4s2
you can before of after 4s
2. (Original post by Dyl98an)
No in general. Because sometimes the 3d orbital comes after. How would you know when to write 3d after 4s2
It doesn't matter, stylistically I think it looks better 4s^2 3d^10 if there are no p orbital electrons and better 3d^10 4s^2 4p^6 f there are. But yeah, it shouldn't matter the mark schemes will have both, and I don't think I've seen any elements heavier than zinc in a past paper (other than the halogens and group 2, but we weren't asked for electronic structure!)
3. In edexcel AS, do we need to know how to construct a born haber cycle?
4. (Original post by itsConnor_)
Could someone help me with this question please? http://gyazo.com/5b8aca37091d74dc3e68fdb651e64a05

Answers are SO4^2 and ClO2^- but I don't understand how this corresponds with the oxidation numbers..could someone help pls?
You know that it's going to be SOx2- (where x is undefined). The oxidation state of S is six, and the overall charge is 2-. Oxygen is usually 2-, so (+6) + x(-2) = -2 ... x = 4. I hope that helps.
5. Apparently ions have a different electron configuration??
6. How would you answer the following questions for 3 marks each:
Explain why the first ionisation energy of group 6 is less than that of group 5 elements?
Why is the first ionisation energy of group 3 lower than group 2??
Thanks

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7. How do you find out the relative abundance? Anyone? I kind of understand how to for percentage abundance, but not when it's not percentage!!

The question is m/z 113 and m/z 115. the relative atomic mass is 114.5. whats the relative abundance!!!!!!
8. Definition of 1st ionisation energy?
ohh good im gonna trying IAL jan 2014 and juen 2014 paper now

Where can I get a hold of these papers? It'd be nice to get some new material to try.
10. (Original post by xMillnsy)
Definition of 1st ionisation energy?
Energy required to remove the outer electron from each atom in one mole of gaseous atoms of an element to produce one mole of gaseous 1+ ions.
11. how do you work out the mass number?!?!
12. (Original post by lukejoshjames)
Energy required to remove the outer electron from each atom in one mole of gaseous atoms of an element to produce one mole of gaseous 1+ ions.
Thank you
13. (Original post by corpeal)
In edexcel AS, do we need to know how to construct a born haber cycle?
yes my friend it has come for the 6 papers even IAL its very easy to be honest
14. (Original post by Signorina)
How do you find out the relative abundance? Anyone? I kind of understand how to for percentage abundance, but not when it's not percentage!!

The question is m/z 113 and m/z 115. the relative atomic mass is 114.5. whats the relative abundance!!!!!!
Well, the way I would do it is see the difference between them, which is 2, and the difference between the lowest value and the RAM, which is 1.5. Then I would divide 1.5 by 2 to get 0.75, so that would be the relative abundance of the higher value.
Therefore: 25% 113 and 75% 115.

Not very technical, but worked for me :P
15. (Original post by S1r)
Where can I get a hold of these papers? It'd be nice to get some new material to try.
message me i ll send it to your email
16. (Original post by gabby07)
Hi I was just wondering - are we allowed to discuss the papers as soon as they're out? Or are the rules same as GCSE (where they have international students still haven't sat them)?
I believe after the exam we can dicuss the answer there is no harm there
can anyone help me on jan 2014 IAl unit 1 edexcel chemistry Question 9 10 11 12 multiple cjoice wih the method please

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18. thank you so much
19. (Original post by shakeyboy)
how do you work out the mass number?!?!

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20. (Original post by Super199)
Can someone explain dative covalent bonding I have never really got it.
like how do you work out if it is a dative covalent bond and which element is giving the lone pair of electrons
can someone explain using phosphine PH3 to form PH4+.
The specific question is to give the name of the type of bond formed when phosphine reacts with an H+ ion. Explain how it is formed
Basically Phosphorous has a lone pair of electrons and it donates them to the hydrogen atom
This is what happens in all dative bonds: a lone pair of electrons is donated to another atom in a covalent
bond

The ones you need to know are NH3BF3, H3O-, NH4+ would you like me to draw them and explain?

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Updated: July 24, 2017
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