system
Given the following post, respond as if you're commenting on Reddit:
human
Why do electrons orbit the nucleus? And why don't the molecules touch each other?

Why would electrons orbit around the atom's nucleus since they are oppositely charged, shouldn't the electrons move to nucleus?

Also, when the molecules attract each other (van der waal) why don't they touch each other? What is the force that prevents them from touching? I think its the kinetic energy they have, so is that kinetic energy converted to work done against the attraction? If so won't the temperature decrease? 

Thanks for the help :)
gpt
Electrons behave quantum-mechanically. In quantum mechanics, a particle has lower kinetic energy if it's more spread out in space. (and it cannot have exactly zero kinetic energy. But as with classical physics, its potential energy will be lowest if it's as close as possible to the nucleus. So these two forces 'balance out' to give atoms the 'size' they have.

>Also, when the molecules attract each other (van der waal) why don't they touch each other? 

How do you define 'touch'? The electron 'cloud' around the atoms is a diffuse thing, so there's no set boundaries. As two molecules get closer and closer, the electrical repulsion between the electrons (in combination with the 'rules' of how they behave) will eventually become larger than the attractive force.