It is vitally important for their understanding of chemistry that they understand that molecules are three-dimensional things and that they have a spatial requirement in that they have a shape of their own and that shape will change. They can't do higher level manipulations without an understanding of three-dimensional nature of molecules.
I think for a lot of people, before they started chemistry, especially if they haven't done any chemistry before, they've got no real understanding of the difference between macroscopic things and microscopic and atomic sized things. We all know how important that distinction is.
When you think of things in terms of energy you can represent energy … energy can be modelled as a particle, as matter. It can be modelled using waves and then trying to talk about how we would use each model as it's appropriate for a particular situation. It's the sort of things we observe might dictate which model we use to explain it, by recognising that in each case there is another model but perhaps just not as useful. So maybe it goes back to just trying to show that everything that we do is a model, every model has its upside and its downside and that we usually only use a model t
This understanding builds students' knowledge about the basic structure of matter which stimulates them to think in sub-microscopic level that provides the fundamental understanding for further chemistry learning.
Try to show students that the fundamental form of matter is energy. Then that this can be represented as particles with mass or as waves (wave functions). Then try to show them that we use the model particle/wave that best helps us understand different phenomena. In class I often do this by asking questions about wave mechanics in particle terms. eg. If a 2s orbital has a node how can the electron pass accross it? Then explain to them the limitations and advantages of each approach.
Try and get across the bigger picture - everything you're going to do is going to be a model. Nothing is going to be right. Nothing is going to be wrong. Nothing is going to be exactly the way it is. Everything is a series of models.
Try to show students that the fundamental form of matter is energy. Then that this can be represented as particles with mass or as waves (wave functions). Link to YouTube Video: Particles and Waves
Students come in, like all of us, trying to apply macroscopic analogies to everything – (the billiard balls colliding and similar things) and using them as models for atoms. Try to get across that it's a simple analogy but it's not as simple as that in reality. I guess go back a step and try and show that everything is really just a form of energy.
You can get the students to physically feel that liquids are not compressible by giving them three closed syringes: one contains water, say 50 mL, that’s been put in the freezer to become ice; another syringe contains 50 mL of liquid water, and the other one is gas. Ask them to push the syringes and see what happens. They find they cannot push the syringes containing liquid or solid, even though they think there would be some space in the liquid one. The misconception is that liquids fall somewhere between solid and gas and so should be “a bit” compressible.
