Suggest why the melting point of sodium Iodide is lower than the melting point of...

of Sodium Bromide.. (1)

The answer: Iodine is bigger

My thoughts: That's a stupid answer. I thought about this way too much for that to be correct. Iodine is less electronegative then Br. So, there's a greater difference in electronegativity btwn Na and Br than Na and I. Weaker permanent dipole dipole forces btwn Na-I molecules.

Also what does being a bigger molecules have to do with lower melting point? its not the bonds that we are breaking, right? only the IMF....

Have a think about the type of bonding you're concerned with here...

if I'm not mistaken the ionic bonds are broken

have you studied polarization yet? and it's effects on melting and boiling points?
P.S. I know we're not supposed to tell answers, just asking in case vix.xvi hasn't studied it yet

ahhh but hold on... remember how you must've studied in IGCSE or GCSE that ionic compounds conduct when their in solution or MOLTEN? that's because the bonds break and they can move about freely even when they melt I think

hmmm like polar molecules? xx

basically, the iodine ion is larger so the forces of attraction between it's protons and electrons are weak while the sodium ion is small and is positively charged so it attracts the iodide ion's electron cloud. the compound isn't completely ionic anymore. are you in GCSE or a levels?

a level xx

oh **** its ionic isnt it

jeez this is annoying lollll

So cuz I is bigger the electrostatic forces are weaker.... i see

thanks for ur help guysss xxx srsly appreciate it




hmmm like polar molecules? xx

basically, the iodide ion is larger so the forces of attraction between it's protons and electrons are weak while the sodium ion is small and is positively charged so it attracts the iodide ion's electron cloud and polarizes the iodide ion. the compound isn't completely ionic anymore. it has some covalent character which results in a decrease in it's melting point. are you in GCSE or a levels? if you're doing your GCSEs you don't need to know this

oh alright. I edited my post, hopefully it'll make more sense now.