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    (Original post by Miss Anonymous)
    I NEED HELP WITH CHEMISTRY!!! Anyone willing to help me?

    Na [2,8] +

    Cl [2,8,8]-

    These two bond to make NaCl... so Cl(-) gains an electron because it has 7 electrons in its outer shell right?
    and Na(+) loses one because it has 1 electron in its outer shell

    What confuses me is, electrolysis.
    e.g. Pb(2+) + 2e(-) -> Pb
    At the cathode, apparently Pb(2+) gains two electrons.

    Why is this? Does Pb(2+) here mean something else and not 'has 2 electrons in the outer shell' - in which case it has to lose, not gain?

    I don't get it :'(

    Someone please help!

    thanks
    Non-metals always form anions (-ions), metals always form cations (+ions). Basically metals give away electrons, non-metals take them.

    Pb2+ means that the lead particle has lost two electrons meaning there are 2 more protons than electrons. Incidentally that does mean there are 2 electrons in the outermost shell because lead is in group 4.

    The cathode is the negative electrode, so it attracts the positive cations. The cathode is negative because it has an excess of electrons, which it gives to the lead ions making them into lead ions.
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    (Original post by ThisIsOurDecision)
    Non-metals always form anions (-ions), metals always form cations (+ions). Basically metals give away electrons, non-metals take them.

    Pb2+ means that the lead particle has lost two electrons meaning there are 2 more protons than electrons. Incidentally that does mean there are 2 electrons in the outermost shell because lead is in group 4.

    The cathode is the negative electrode, so it attracts the positive cations. The cathode is negative because it has an excess of electrons, which it gives to the lead ions making them into lead ions.
    ahha I get it

    so does the plus sign there doesn't have anything to do with e.g. Na [2,8] + having 1 electrons on its outer shell?
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    (Original post by Miss Anonymous)
    ahha I get it

    so does the plus sign there doesn't have anything to do with e.g. Na [2,8] + having 1 electrons on its outer shell?
    Na+ would mean that the sodium had lost one electron. You would know this because for it to be Na+ there has to be more protons than electrons, in this case, 1 more.
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    (Original post by ThisIsOurDecision)
    Na+ would mean that the sodium had lost one electron. You would know this because for it to be Na+ there has to be more protons than electrons, in this case, 1 more.
    Figured out where i got confused thanks =] feeling stupid now lol

    +rep
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    Miss we dont need to learn about Pb? lol. Only electololysis of Brime and Copper from impure copper^^
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    (Original post by TheFootyKing19)
    What topics do you think will turn up?
    My teacher went on a AQA teacher's training day and was told that if an subject from the syllabus that does not appear in two years of examinations, it must appear in the next exam. I don't know if that helps but yeah...
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    Miss can you help me with a question for CHY2H June 08 paper.

    1 (c) A tube of toothpaste contains 1.2 g of SnF2 .
    Calculate the mass of fluorine in this tube of toothpaste.

    the answer to 1b, for the percentage mass of Fluorine is; 24.2

    However how am i suppose to get the mass of fluorine not % mass. In the markscheme for 1 c it says do 24.2/100 x 1.2 why are you suppose to do the percentage mass over 100?
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    Also, as you are very good in physics , can you help me understand nuclear fission. I dont get it, how do they fire neutrons at radioactive material... isent the neutron in an atom lol?.. so how do they get that neutron only by it self and fire it at radioactive material which absorbs it, breaking down the nuclei into 2 and releasing more neutrons. also in beta decay its the neutron that splits to give protons and electrons... the proton in left there but the electon is ejected as a beta emmision. How do we get inside a neuton protons and electrons??? lol
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    (Original post by king101)
    Miss can you help me with a question for CHY2H June 08 paper.

    1 (c) A tube of toothpaste contains 1.2 g of SnF2 .
    Calculate the mass of fluorine in this tube of toothpaste.

    the answer to 1b, for the percentage mass of Fluorine is; 24.2

    However how am i suppose to get the mass of fluorine not % mass. In the markscheme for 1 c it says do 24.2/100 x 1.2 why are you suppose to do the percentage mass over 100?
    Because if 24.2% of SnF2 is flourine (F2) then you want to find 24.2% of 1.2g
    Thus 24.2/100 x 1.2 is the same as 1.2/100 x 24.2. which is finding 1% of 1.2 then multiplying it to get 24.2%. Hope that clears it up?
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    Ah yes thanks .
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    (Original post by king101)
    Also, as you are very good in physics , can you help me understand nuclear fission. I dont get it, how do they fire neutrons at radioactive material... isent the neutron in an atom lol?.. so how do they get that neutron only by it self and fire it at radioactive material which absorbs it, breaking down the nuclei into 2 and releasing more neutrons. also in beta decay its the neutron that splits to give protons and electrons... the proton in left there but the electon is ejected as a beta emmision. How do we get inside a neuton protons and electrons??? lol
    Nuclear fission/fusion is my least favourite topic in physics (if you’ve seen my post above lol)
    Anyway,
    “the neutron in an atom lol?.. so how do they get that neutron only by it self”
    No idea how…
    Hmm.. (just my guess) I think nucleus could be split with lots of energy
    And since isotopes exist (same number of protons but diff number of neutrons), that certainly means somehow neutrons can get on its own?
    “fire it at radioactive material which absorbs it, breaking down the nuclei into 2 and releasing more neutrons”
    I asked my teacher why it always turns to 2 nuclei and 2-3 neutrons and she said it’s beyond GCSE level but there are actually ways of knowing how the nucleus will split when neutron hits it. (some kind of calculation? Like energy calculation or something and apparently we can figure out how it will split. Lol donno)
    “also in beta decay its the neutron that splits to give protons and electrons... the proton in left there but the electon is ejected as a beta emmision.”
    I thought electron’s emitted, and as a result neutron turns to proton? (because beta particles are electrons)

    Hope this helps~ (actually, I don’t think this will help :'( )
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    it did help a little thx lol so the electrons are sorta the beta particles i got it..

    one more thing;

    fusion- this is the joining of 2 nuclei to form a bigger one. (So we can have 2 atoms joining together as they have nuclei in them therfore joining them together, or is it only somthing without electrons?) So were do this happen naturaly?
    fission- where does this happen naturaly?
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    (Original post by king101)
    it did help a little thx lol so the electrons are sorta the beta particles i got it..

    one more thing;

    fusion- this is the joining of 2 nuclei to form a bigger one. (So we can have 2 atoms joining together as they have nuclei in them therfore joining them together, or is it only somthing without electrons?) So were do this happen naturaly?
    In the sun. Hydrogen isotopes are fused to make helium, this gives out energy. Larger suns can fuse heavier elements together to give things like Iron etc.

    (Original post by king101)
    fission- where does this happen naturaly?
    In any unstable (radioactive) nucleus, such as Uranium.

    It's all a balance of the forces inside the nucleus. If two nuclei can be fused to make a more stable nucleus, then energy is given out. If a nucleus can be split to give 2 or more stable nuclei, energy is again given out. It's a little more complicated than this (strong and weak nuclear forces and all) but it's a easy way to think about it.
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    (Original post by gingerbreadman85)
    In the sun. Hydrogen isotopes are fused to make helium, this gives out energy. Larger suns can fuse heavier elements together to give things like Iron etc.


    In any unstable (radioactive) nucleus, such as Uranium.

    It's all a balance of the forces inside the nucleus. If two nuclei can be fused to make a more stable nucleus, then energy is given out. If a nucleus can be split to give 2 or more stable nuclei, energy is again given out. It's a little more complicated than this (strong and weak nuclear forces and all) but it's a easy way to think about it.
    Thanks Ginger Bread! Does it have to be in the sun though to, go through the process of fusion? Does it have to get rid of the electrons through high tempreature?
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    (Original post by king101)
    Thanks Ginger Bread! Does it have to be in the sun though to, go through the process of fusion? Does it have to get rid of the electrons through high tempreature?
    Yes, fusion is normally plasma (atoms stripped of electrons) as the electron shells of colliding atoms will of course repel each other.

    The conditions can be replicated (have a look at ITER or other fusion reactors).
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    If anybody wants some free AQA GCSE science resources, see my thread:

    http://www.thestudentroom.co.uk/show....php?t=1503576

    thanks and good luck to everyone! x
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    Ah I understand it know . So lemme just clear up, fission and fussion both occur in unstable issotopes and it occurs in the nuclei for both..

    Fission= Neutrons absorbed by, the isotope radioactive nuclie....
    Fussion= Joining of 2 unstable nuceli in other words isotopes.....

    am i right>
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    And what is the difference between hard and strong?
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    Dam anyone else getting B's on the past paper for physics and biology i do like 1-3 marks of an A though :/
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    (Original post by king101)
    And what is the difference between hard and strong?
    What's this for? Chemistry?

 
 
 
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