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> Any Chemists Out There?, Possibly a silly question
Fran*Piano
post Mar 31 2010, 05:06 PM
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I know that this is a music forum, but I'm really stuck here (IMG:style_emoticons/default/sad.gif) I'm trying to revise for GCSE chemistry, as my exam is pretty soon after going back to school. My teacher is off this week, and I just can't get my head round this one particular thing.
We've been studying the periodic table, specifically the alkali metals and the halogens, and we're doing about reactivity-I understand the most reactive alkali metal is at the bottom of the group, and the most reactive halogen is at the top, but I don't understand why! I know it's something to do with nucleus shielding, but I just don't get it...would any wonderful person be able to give me any sort of idea?
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Cyrilla
post Mar 31 2010, 05:06 PM
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f#m might be able to help, I think..

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Babybird2
post Mar 31 2010, 05:16 PM
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For the alkali metals, I think it's because the electron in the outer shell is furthest away from the nucleus the further down the group you go, so it is held less tightly.

For the halogens, these react to complete their outer shell. At the top of the group, the outer shell is closer to the nucleus compared to the bottom so an electron can join more easily.

Someone will no doubt tell me I'm wrong though (IMG:style_emoticons/default/laugh.gif)
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fsharpminor
post Mar 31 2010, 05:45 PM
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Ha ! Cyrilla put me on the spot , but yes Babybirds answer is correct. I'm using an iPhone at the moment so it's a bit fiddly to go into detail .

The halogens react by completion , so their reactivity is F greater than Cl greater than Br . For alkalinn earths it's the other way round for the opposite reason K being more reactive than Na etc
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Fran*Piano
post Mar 31 2010, 06:18 PM
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Babybird and Fsharpminor, you are both wonderful people, thank you very much! (IMG:style_emoticons/default/biggrin.gif)
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Stephie
post Mar 31 2010, 08:33 PM
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Is it terrible that I remember absolutely NONE of this from GCSE Chemistry? (IMG:style_emoticons/default/huh.gif) It was only three and a half years ago...
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stetenorve
post Mar 31 2010, 09:42 PM
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Was Mr fsharpminor speaking English or Klingon? (IMG:style_emoticons/default/unsure.gif)
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Fran*Piano
post Mar 31 2010, 09:56 PM
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QUOTE(stetenorve @ Mar 31 2010, 10:42 PM) *

Was Mr fsharpminor speaking English or Klingon? (IMG:style_emoticons/default/unsure.gif)


(IMG:style_emoticons/default/laugh.gif) (IMG:style_emoticons/default/laugh.gif) he was being extremely helpful, that's what (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/biggrin.gif)
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Stephie
post Apr 1 2010, 12:18 AM
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QUOTE(stetenorve @ Mar 31 2010, 10:42 PM) *

Was Mr fsharpminor speaking English or Klingon? (IMG:style_emoticons/default/unsure.gif)

Klingon, for sure. *nod* (IMG:style_emoticons/default/tongue.gif)
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fsharpminor
post Apr 1 2010, 07:41 AM
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(IMG:style_emoticons/default/rofl.gif) (IMG:style_emoticons/default/rofl.gif) (IMG:style_emoticons/default/rofl.gif)
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