6.022*10^23 molecules
4*6.022*10^23 atoms = 24.08*10^23 atoms
I think the answer would be the number of electron in pairs that is around the central atom. This is the most general principle in determining structure of a molecule. Electrons are the ones responsible in bonding with other atoms. Hope this helped.
B compressed spring I’m pretty sure
A homogeneous mixture has the same uniform appearance and composition throughout. A heterogeneous mixture consists of visibly different substances or phases. Homogeneous mixtures
So the answer is heterogeneous.