Limitations of Models (1 Viewer)

[untitled....]

hey,
i've got this assignment due tomorrow and i'mstuck on this part
"discuss the limitations of models of ionic lattices, covalent molecules and covalent and metallic lattices"

any help would be appreciated

thanks

 

[xiao1985]

one of the things you could talk about is that for covalent molecule, the model suggests that the electrons forms a solid, rigid bond. Whilst it is true to a certain extend, electrons do move. This mobility is not captured by this form of modelling.

 

[namburger]

Limitations include:

1. The ionic, covalent and metallic bonding all have different strengths of attraction. Using models, the bonds can't illustrate these different strengths. (covalent molecular are weak, whereas metallic bonding is strong)

2. Unable to see the different properties (hardness, malleability or brittleness) of the different compounds. ( Covalent network is hard and brittle whereas, metals are hard and malleable)

3. Metals are positive ions surrounded by a sea of delocalised electrons which can't be shown by models. (same with covalent molecular. i.e. sharing of e-) As xiao said, mobility can't be seen

 

[rooeys2]

omg is this prelim chem cuz i forgot about this stuff

 

[untitled....]

thanks 4 that