Which experiment led to the idea that atoms contained a nucleus?

What is important to study for nios grade 12 chemistry? i have only one month left.

Compare and contrast the bohr model and the electron cloud models of the atom.

How is energy related to the change of state represented by the model? atoms gain energy as a solid changes to a liquid. atoms gain energy as a solid changes to a gas. atoms lose energy as a solid changes to a liquid. atoms lose energy as a solid changes to a gas.