[atomic]

we are to do a lab soon. And the topic is to pick a property of the compound (ie. density, alkalinity, atomic radius?) and speculate the correlation between that property and heat of solution. I picked density because it seemed the easiest (though atomic radius does sound fun!). I must write a general statement (ie. if we were talking about something that involved Q=mcdelta"t", I would talk about that, and  mention that), and so i need one for this. did anyone, anywhere say anything that could correspond to what I am talking about?


By the way if this makes me seem like I know what I am talking about-I don't. So dumb-ify the language if you can answer, please? Thank you?

And just for my knowledge's sake? If anyone can give a little information on what atomic radius is and how it might correspond to the heat of solution? Though that is not necessary)
PS: if my iron nitrate has a 9H2O after it, what does that signify?