There was little change in the understanding of the atom until John ... Bohr revised Rutherford's model by suggesting that the electrons orbited the nucleus in different energy levels or at ...

It also tells us that chlorine has 18 neutrons (35 - 17) and, as the number of electrons and protons are equal in a neutral atom ... same number of protons but different numbers of neutrons.

Electrons are in regions around the nucleus that are different distances away from the nucleus ... like the model that looks like a target. This energy level model shows two electrons on the first ...

Explain that scientists use models of atoms to see the different ways atoms can connect together to make molecules ... Explain that a water molecule has two hydrogen atoms and one oxygen atom. Ask ...