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VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: kettles on April 06, 2011, 08:16:41 pm

Title: melting and boiling point question
Post by: kettles on April 06, 2011, 08:16:41 pm
hey, can someone please explain to me why an ion of smaller size will result in a much greater melting point. Also, why an ion of greater charge results in a greater melting point. thanks :D
Title: Re: melting and boiling point question
Post by: bomb on April 06, 2011, 08:18:38 pm
it's to do with the strength of the bonding between molecules - the stronger the bonds, the more energy it takes to pull them apart :)
i haven't directly answered your question, but think about it :)
Title: Re: melting and boiling point question
Post by: kettles on April 06, 2011, 08:24:28 pm
i desperately need help :O
Title: Re: melting and boiling point question
Post by: Water on April 06, 2011, 08:34:43 pm
:For ions, think about ionisation energy, core charge and electro negativity. You grasp these 3 concepts, it'll answer your question :)
Title: Re: melting and boiling point question
Post by: kettles on April 06, 2011, 08:40:23 pm
is this correct? please correct me if i get it wrong :D.

Ions of much smaller sizes result in a much greater melting temperature because their core charge(Attraction between valance electrons and nucleus) is much greater than those with larger masses. a larger atom will contain inner shells which tends to weaken the core charge.

Ions with greater charge will result in a much greater melting temperature because much more energy is required to bond these two ions together in comparison to a lower charge ion. higher energy= greater melting temperature.

I think i understand the size part but not too sure on the 'more' charge one :S
Title: Re: melting and boiling point question
Post by: iNerd on April 06, 2011, 08:41:36 pm
is this correct? please correct me if i get it wrong :D.

Ions of much smaller sizes result in a much greater melting temperature because their core charge(Attraction between valance electrons and nucleus) is much greater than those with larger masses. a larger atom will contain inner shells which tends to weaken the core charge.

Ions with greater charge will result in a much greater melting temperature because much more energy is required to bond these two ions together in comparison to a lower charge ion. higher energy= greater melting temperature.

I think i understand the size part but not too sure on the 'more' charge one :S
Core charge remains constant down a group and size increases down a group so size has nothing to do with it? :S

Meh I don't know I'm y11 - someone will confirm :P