All an atom is is a tiny weeny nucleus with electrons orbiting it. Most of the atom is empty space. I think the analogy is the atom was the size of a football stadium, the nucleus would be the size of the football.

 

 

 

Anyway, an atoms shape is presumably determined by the electrons orbiting it, and because you cannot pin down a single electron with a position and velocity they kind of blur as to where they are, you can only represent the probability of where an electron might be at any moment in time. Electrons inhabit certain discrete orbitals, which are necessarily mainly circular in shape because that's the way they "orbit" the nucleus. A sphere is a preferred shape in physics for orbits of electrons.

 

 

 

It's a funny thing to think about, you can't really compress electrons into appearing into different areas and therefore change the shape of the atom. You can compress an atom, but that requires spectacularly large amounts of gravitational strength or pressure.

 

 

 

A lot of it is quantum mechanics, which I don't know that much about, so i'll just leave my speculation at that.

 

 

 

Well the shape of orbitals change during hybridization don't they? The atom would be changing shape, but it is a predefined shape and another atom is getting involved, but still.

 

 

 

Sorry yeah, I should say orbitals are predefined anyway, not necessarily fixed, but not, err...ductile?

 

 

 

Malleable?

for the same reason you can't pull your head out of your [wagon].

 

 

 

assuming you cant.