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    Can someone explain why elements in group 1 have a lower melting/boiling point as the peroid increase, but group 7 elements,halogens, increase in melting temp as the peroid increases. i assume it is something to do with the need for gaining losing electrons aand therefore the ease is opposite on either side of the peroidic table ie
    if an element is tryin to lose an electron,group1, then the further from the nucleus the easier and more reactive but in group 7 the less quantum shells then the more attraction to pull electrons to it,

    pleas ehelp
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    sounds fun - im meant to be revising chemistry now - just look in the revision book
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    (Original post by Meat Loaf Rocks)
    Can someone explain why elements in group 1 have a lower melting/boiling point as the peroid increase, but group 7 elements,halogens, increase in melting temp as the peroid increases. i assume it is something to do with the need for gaining losing electrons aand therefore the ease is opposite on either side of the peroidic table ie
    if an element is tryin to lose an electron,group1, then the further from the nucleus the easier and more reactive but in group 7 the less quantum shells then the more attraction to pull electrons to it,

    pleas ehelp
    This is to do with the sizes of the atoms.

    Group 1: As you go down the period, the atoms become larger, but they all release only 1 electron for metallic bonding. This means that the attraction to the pool of electrons decreases as you go down the group due to the increasing atom size and increased shielding.

    Group 7: The melting/boiling points of these elements are determined by the Van der Waals forces between the dimers, as they exist as Cl2 etc. As the elements increase in size, the electron cloud surrounding the molecules becomes more moveable, and so greater dipoles can be formed increasing dipole - dipole interactions.
 
 
 
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