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Metals/non-metals, ions and their charges watch

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    Hi,

    I've got an exam on Monday and I'm a bit confused about charges, ions, etc.

    I thought a metal such as Na was negatively charged because it has one too many electrons. So why are Li, Na, etc. called Li+, Na+, and so on? And the same for non-metals, why are they called Cl- when they need an electron?

    Also, are Li ions the same as the sign, e.g. Li+ produces + ions?

    An example would be helpful.

    Thanks!

    Edit: if you have a metal or non-metal with four electrons in its outer shell, how can I tell whether it gains or loses electrons?
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    (Original post by addylad)
    Hi,

    I've got an exam on Monday and I'm a bit confused about charges, ions, etc.

    I thought a metal such as Na was negatively charged because it has one too many electrons. So why are Li, Na, etc. called Li+, Na+, and so on? And the same for non-metals, why are they called Cl- when they need an electron?

    Also, are Li ions the same as the sign, e.g. Li+ produces + ions?

    An example would be helpful.
    Thanks!
    Na forms a positive ion by losing an electron to become Na+
    Cl gains an electron to complete its outer electron level, and becomes Cl-
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    Take a look at the electronic structure of the neutral atoms - for Na you have 2, 8, 1 so for it to have a full outer shell it needs to lose an electron maing a positive ion : Na ---> Na+ + e-

    The opposite case for chlorine - it needs to gain an electron to have a full outer shell Cl + e- ---> Cl- leaving a negative ion.
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    Oh and metals always form positive ions because they lose electron(s).
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    Just remember it by group mate

    If the element is in Groups 1-3 + transition, it will be a + charge...

    Li+, Cu2+, Al3+, Mg2+, Na+, K+ etc

    Groups 5-7 are - charge

    Cl-, I-, O2-, F-

    So i wrote on top of each of my groups

    +1 +2 +3 +/-4(dont really need that) -3 -2 -1 0

    Im assuming you're doing gcse.... so no subshells and stuff.. right?
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    Ok Li and Na and like metals are all in group one, so it is easier to lose and electron and become a psoitive ion than gain any and still have spaces in the 3s shell, remember ions like to stay stable and the only of acheving this is to either have a half full or full outer shell, by the easiest means possible

    Hope this helps
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    Thanks for all the quick replies, and yes I'm doing GCSE seperate sciences.
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    (Original post by EierVonSatan)
    Take a look at the electronic structure of the neutral atoms - for Na you have 2, 8, 1 so for it to have a full outer shell it needs to lose an electron maing a positive ion : Na ---> Na+ + e-

    The opposite case for chlorine - it needs to gain an electron to have a full outer shell Cl + e- ---> Cl- leaving a negative ion.
    So what charge would it have before it has lost its electron?
    Thanks.
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    Metallic elements like sodium or potassium give up electrons as that is the easiest way to obtain a full outer shell of electrons. Gaseous elements like Chlorine receive electrons to fill their outer level to the full and thus gain negative charges. All in all:

    Metallic elements are electron donors and Gaseous elements are electron receivers
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    (Original post by addylad)
    So what charge would it have before it has lost its electron?
    Thanks.
    You mean the Na? It's just the neutral atom (no charge).
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    (Original post by addylad)
    So what charge would it have before it has lost its electron?
    Thanks.
    All atoms are neutral before they lose/gain electrons (i.e the no. of protons (+) is equal to the no. of electrons (-) and so the charges are balanced)
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    (Original post by EierVonSatan)
    You mean the Na? It's just the neutral atom (no charge).
    Ah I see so it is like a balance, and when Na loses an electron it has more protons than electrons, making it positively charged.

    All is clear now. Thanks!
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    (Original post by Laith)
    All atoms are neutral before they lose electrons (i.e the no. of protons (+) is equal to the no. of electrons (-) and so the charges are balanced)
    Just what I was thinking.
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    OK, I've got another query about electrolysis.

    I've been told that the metal ions (or atoms/electrons?) move towards the negatively charged cathode and gain electrons. This is because the metal has 'donated' the electron to the non-metal and it's being replaced, right?

    Also, does the half equation for the reaction at the cathode always have one term on the left, and at the anode, one term on the right?

    Thanks!
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    (Original post by addylad)
    OK, I've got another query about electrolysis.

    I've been told that the metal ions (or atoms/electrons?) move towards the negatively charged cathode and gain electrons. This is because the metal has 'donated' the electron to the non-metal and it's being replaced, right?

    Also, does the half equation for the reaction at the cathode always have one term on the left, and at the anode, one term on the right?

    Thanks!
    :eek: you do electrolysis at GCSE?

    If its lost electrons, the half equation has one term to the right

    If gained, it has one term to the left

    and I dont understand the 1st part, If the metal gains electrons its dontated from the cathode
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    (Original post by Loz17)
    :eek: you do electrolysis at GCSE?

    If its lost electrons, the half equation has one term to the right

    If gained, it has one term to the left

    and I dont understand the 1st part, If the metal gains electrons its dontated from the cathode
    Yep, slightly confusing but interesting. The most common ones are lead bromide and copper chloride. I prefer to learn methods, rather than a list of answers (which we are often taught). Hopefully it will help me at A level.

    What I mean is that a metal 'donates' its outer electron(s) to the non-metal (ionic bonding) and then current flows from the cathode and replaces the electron(s) which the metal has just lost. At the same time, the non-metal is losing electrons to the anode in a cycle.

    These are my thoughts. Are they correct?

    Hope this makes sense.
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    (Original post by addylad)
    Yep, slightly confusing but interesting. The most common ones are lead bromide and copper chloride. I prefer to learn methods, rather than a list of answers (which we are often taught). Hopefully it will help me at A level.

    What I mean is that a metal 'donates' its outer electron(s) to the non-metal (ionic bonding) and then current flows from the cathode and replaces the electron(s) which the metal has just lost. At the same time, the non-metal is losing electrons to the anode in a cycle.

    These are my thoughts. Are they correct?

    Hope this makes sense.
    It makes sense but not quite right

    Basically its not ionic bonding and there is no non-metal (not that it matters), its a redox reaction (i don't expect you to know what that is). What it is is that say at the cathode you have a thin sheet of pure copper(Cu atoms), and at the anode you have a sheet of impure copper (Cu2+ ions). And surrounding is a warm solution of copper (II) sulphate and sulphuric acid (also known as electrolyte, but ignore this, its just the conditions the eletrodes need to be in).

    Keep this in mind for basic oxidation and reduction reactions (Redox reactions because they occurs simultaneously) OIL RIG (oxidation is the loss of electrons and reduction is the gain of electrons)

    So at the cathode with pure copper you get the half equation Cu2+(aq) +2e -->Cu(s), deposting copper onto the electrode (the Cu2+(aq) ios are in the eletrolyte).

    At the anode with impure copper, the half equation is Cu (s) --> Cu2+ (aq) + 2e. So copper is dissolved into the electrolyte.

    To be honest you don't need to worry about this until AS, and if your doing it and understand it now, you will be on course for an A in chemistry at A level for sure

    This is taken from my A-level chemistry course book

    If you don't understand let me know. It is a little vauge I know, but not done it for a while
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    Well I am at GCSE and we do electrolysis

    Take an example of NaCl in water.

    The NaCl dissolves in water, as the slight positive charges on the hydrogens and negative of the oxygens in the water molecule pull the crystal apart. As you know, ionic lattices like NaCl already contain charged sodium + and charged chloride -. The Sodium ions are attracted to the oxygen pole of the water and the chloride ions to the hydrogen poles. This tears the lattice apparts and leaves ions. When electrolysis occurs, the electrolytes are attracted to the electrodes. A current can flow because the ions are free to move with the electrical potential. At the anode (+) the anions (-, chloride in this case) are oxidised, which means they lose electrons and current can flow. At the cathode (-) cations (+, sodium in this case) are reduced, which means they gain electrons.

    That is the basis of electrochemistry.
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    (Original post by Laith)
    Well I am at GCSE and we do electrolysis

    Take an example of NaCl in water.

    The NaCl dissolves in water, as the slight positive charges on the hydrogens and negative of the oxygens in the water molecule pull the crystal apart. As you know, ionic lattices like NaCl already contain charged sodium + and charged chloride -. The Sodium ions are attracted to the oxygen pole of the water and the chloride ions to the hydrogen poles. This tears the lattice apparts and leaves ions. When electrolysis occurs, the electrolytes are attracted to the electrodes. A current can flow because the ions are free to move with the electrical potential. At the anode (+) the anions (-, chloride in this case) are oxidised, which means they lose electrons and current can flow. At the cathode (-) cations (+, sodium in this case) are reduced, which means they gain electrons.

    That is the basis of electrochemistry.
    God I'm at A2 and you can explain it better than me
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    (Original post by Loz17)
    God I'm at A2 and you can explain it better than me
    lol thanks i spent a long time learning this
 
 
 
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