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Author Topic: Edexcel CHEMISTRY DOUBTS!!!!  (Read 254030 times)

Offline Kim

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #165 on: May 20, 2010, 05:35:02 pm »
Quote from: raimunts on May 20, 2010, 05:31:25 pm
4 The first five ionization energies of an element, Z, are:
  790, 1600, 3200, 4400, 16100 kJ mol–1
  In which group of the Periodic Table is Z found?
           A 2
           B 3
           C 4
           D 5


Answer is C 4.
How can you tell?

u can see in the question dat are 3 jumps
from 790 to1600
1600 to 3200
4400 to 16100
which means it has 4 shells (as one jump means that nxt electron is from another shell closer to the nucleus)
so group 4
do u get it?
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Offline raimunts

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #166 on: May 20, 2010, 05:39:45 pm »
No I still dont get it! How can 4 SHELLS mean group 4!!
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Offline Darth Austrakast

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #167 on: May 20, 2010, 05:39:57 pm »
Yes cuz after the 4th ionization energy there is a huge jump-the 5th ionization energy corresponds to the 5th electron.Since there is a such a huge gap between 4th and 5th it implies that all the 5th electron removed was from another shell. Group IV elements have 4 electrons on their last shell so it is Group IV
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Offline Darth Austrakast

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #168 on: May 20, 2010, 05:41:47 pm »
Quote from: kim on May 20, 2010, 05:35:02 pm
u can see in the question dat are 3 jumps
from 790 to1600
1600 to 3200
4400 to 16100
which means it has 4 shells (as one jump means that nxt electron is from another shell closer to the nucleus)
so group 4
do u get it?

kim dnt confuse its NOT shells ITS ELECTRONS
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Offline raimunts

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #169 on: May 20, 2010, 05:42:51 pm »
Quote from: Austrakast on May 20, 2010, 05:39:57 pm
Yes cuz after the 4th ionization energy there is a huge jump-the 5th ionization energy corresponds to the 5th electron.Since there is a such a huge gap between 4th and 5th it implies that all the 5th electron removed was from another shell. Group IV elements have 4 electrons on their last shell so it is Group IV

Got it now...4 electrons not shells. Thanx to both..austrkast and kim :)
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Offline Kim

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #170 on: May 20, 2010, 05:43:01 pm »
Quote from: Austrakast on May 20, 2010, 05:41:47 pm
kim dnt confuse its NOT shells ITS ELECTRONS

ok sorry
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Offline Kim

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #171 on: May 20, 2010, 06:00:00 pm »
hey
cud sumone help me wid q 18 ai from the sample paper unit 1
why is the energy change 4410 which is half of wat i get??
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Offline Kim

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #172 on: May 20, 2010, 06:04:03 pm »
Quote from: kim on May 20, 2010, 06:00:00 pm
hey
cud sumone help me wid q 18 ai from the sample paper unit 1
why is the energy change 4410 which is half of wat i get??


haha lol no need
i figured it out was using 100 instead of 50
lol so no need
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Offline Igcseboy

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #173 on: May 20, 2010, 06:06:38 pm »
guys and gals.... so wat r u ppl doin for last hours prep??? :S:S:S

any important points???
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Offline Saladin

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #174 on: May 20, 2010, 06:11:09 pm »
Quote from: Igcseboy on May 20, 2010, 06:06:38 pm
guys and gals.... so wat r u ppl doin for last hours prep??? :S:S:S

any important points???

Keep doin papaz!
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Offline Kim

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #175 on: May 20, 2010, 06:14:07 pm »
Quote from: Igcseboy on May 20, 2010, 06:06:38 pm
guys and gals.... so wat r u ppl doin for last hours prep??? :S:S:S

any important points???

well i am just doin papers
try doin sum old papers
and am going to revise everything in my notes and txtbk
have alot of time in the morn as well so will do revision then as well
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Offline Ibiza279

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #176 on: May 20, 2010, 06:16:17 pm »
Quote from: Igcseboy on May 20, 2010, 06:06:38 pm
guys and gals.... so wat r u ppl doin for last hours prep??? :S:S:S

any important points???

jus do the latest papers, they ll give u the general trend of how the questions are asked and check the corresponding mark schemes to noe how the questions should b answered. :)
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Offline Kim

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #177 on: May 20, 2010, 06:32:19 pm »
do we need to know iodine titrations for tomorrow??
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After all is said and done, more is said than done.

By the time a man realizes that maybe his father was right, he usually has a son who thinks he’s wrong.

The early bird may get the worm, but the second mouse gets the cheese.

Offline Darth Austrakast

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #178 on: May 20, 2010, 06:43:37 pm »
nope
thats in U2
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Offline Saladin

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #179 on: May 20, 2010, 06:43:52 pm »
Quote from: kim on May 20, 2010, 06:32:19 pm
do we need to know iodine titrations for tomorrow??

No, thats in Unit 2.
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