Limitations of Lattice Models (1 Viewer)

[Aerath]

Dot point 14: Choose resouces and process information from secondary sources to construct and discuss the limitations of models of ionic lattices, covalent molecules and covalent mettalic lattices.

I'm not exactly sure what sort of things I need to satisfy this dot point. I'm just wondering what topics I need to cover (and if possible, a brief outline). Could anyone help me?

Thanks a ton.

 

[namburger]

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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-)

 

[Aerath]

Thanks.

 

[pratima]

that's not entirely correct though

the malleability of metals can be explained through the non directional nature of their bonds, so when they are stressed they do not break

and ionic substances are brittle because they have directional bonds so when they are stressed then they break