Can Atoms be broken down into simpler substances?

The simple anser to this question is 'no' - an atom if the simplest unit of chemistry. Compounds are made of two or more different types of atom, for example copper carbonate is made of copper atoms linked with carbon and oxygen. Atoms build together to make molecules such as water and carbon dioxide: atoms gain or lose electrons in order to form ions which then hold together in ionic substances such as sodium chloride. So the alert reader will have spotted that if atoms can gain and lose electrons then clearly they are not indivisible. Atoms are made up of three components: in the central nucleus you will find the protons, which have a positive charge, glued together by the neutrons, which don't have a charge (but do have a mass equal to that of the protons). Whizzing about around the outside of the atom you will find the electrons - the same number as you had protons, because the electrons are negatively charged and their total charge must balance the positive charge of the protons to make a neutrally charged atom. The electrons are at different distances in an arrangement of 'shells'. Once you know the arrangement of electrons you are in a position to say how that atoms will behave in relationship withother atoms, and that much knowledge gets you through school science. Then it turns out that the protons and neutrons themselves are made up of little things called quarks, which can be called 'up' and 'down', and protons are made of two up and one down while neutrons are made of one up and two down. Now the really sneaky thing here is that this difference in 'spin' of the quarks makes the neutron weigh a tiny tiny bit less than the proton... with a bit of a jump to thinking about stars, in a star hydrogen atoms (protons) are being joined together into helium atoms (two protons + two neutrons) - so protons are being converted into neutrons - and a tiny tiny bit of mass is being lost, converted into energy. And as Einstein said e=mc2 so if we lose a tiny tiny bit of mass we get as enormous amount of energy out, and that's what is coming out of the stars. Ancient stars went on reacting to make all the elements we have in our universe today. So the entire universe depends on the fact that some quarks are spinning the other way!! And that's why science is an extremely cool thing to know about. By the way. did you notice along the way that you are made of stardust?