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    Hi guys,

    I don't understand why mgcl2 forms over mgcl or mgcl3 could someone explain it too me please

    Thanks
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    Mg has 2 electrons in it's outer orbital where as Cl is missing one in it's outer orbital, therefore the Mg will share an electron with each Cl in the molecule. MgCl2 is therefore more stable.
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    (Original post by tree123)
    Hi guys,

    I don't understand why mgcl2 forms over mgcl or mgcl3 could someone explain it too me please

    Thanks
    In a simple format- Mg is a 2+ ion whereas CL is a 1- ion. Therefore the charges are unequal, in order for them to cancel out and produce a compound you need two CL- ions.
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    It says in the textbook something about: the crystal formed from magnesium and chlorine it which that maximizes the lattice energy. What does that mean?
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    (Original post by tree123)
    It says in the textbook something about: the crystal formed from magnesium and chlorine it which that maximizes the lattice energy. What does that mean?
    For the reasons already given, the ionic bonding will be stronger in the MgCl2 molecules and the atoms will be held closer together.
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    (Original post by Mockery)
    For the reasons already given, the ionic bonding will be stronger in the MgCl2 molecules and the atoms will be held closer together.
    oh ok, so why is this the most exothermic compared with mgcl and mgcl3
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    (Original post by tree123)
    oh ok, so why is this the most exothermic compared with mgcl and mgcl3
    Stronger bonding releases more energy upon breakage.
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    (Original post by Mockery)
    Stronger bonding releases more energy upon breakage.
    ok why is the formation of mgcl3 for endothermic than the formation of mgcl2? Is it because the bonds are not held as strongly?
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    (Original post by Mockery)
    Stronger bonding releases more energy upon breakage.
    No no no no no!!!!!

    Bond breaking is ENDOthermic, it requires energy it does NOT release energy.
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    (Original post by charco)
    No no no no no!!!!!

    Bond breaking is ENDOthermic, it requires energy it does NOT release energy.
    I stand corrected

    These things begin to slip your mind after a while of not studying much chemisty..
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    (Original post by charco)
    No no no no no!!!!!

    Bond breaking is ENDOthermic, it requires energy it does NOT release energy.
    ok why is the formation of mgcl3 endothermic but the formation of mgcl2 exothermic? Is it because the bonds are not held as strongly?
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    (Original post by tree123)
    ok why is the formation of mgcl3 endothermic but the formation of mgcl2 exothermic? Is it because the bonds are not held as strongly?
    In order to understand the answer you need to do the whole Born Haber cycle for each proposed compound...
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    (Original post by tree123)
    ok why is the formation of mgcl3 endothermic but the formation of mgcl2 exothermic? Is it because the bonds are not held as strongly?
    If you think of it like this:

    MgCl2 is already stable with it's noble gas like electron configuration. It's going to repel any more groups of electrons that might try to bond with it - such as those on an incoming Cl atom.

    The electrons on MgCl2 and Cl are going to repel each other. If you want these atoms to bond, then you're going to need to put in energy into the system to allow the electrons to overcome the electrostatic repulsions.

    Of course, it's also probable that I'm just talking out of my ass here, so don't quote me on it.
 
 
 
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