How are atoms different from one another?

Answer 1

They are different because of the number of electrons in there electron cloud.

True, the number of electrons are specific to the type of atom but so are the number of protons. The atomic number of the atom is directly related to the number of protons and electrons it has. So carbon for example is given the atomic number 6. Thus it has 6 protons and 6 electrons. It's Atomic Mass is 12.0107 amu. This we can round to 12. To aquire the atomic mass of a given element you add the number of protons and nuetrons together since the electrons are so infinitely small they are not considered to have any mass. We know from the atomic number that carbon has 6 protons, it's atomic mass is 12, so that means the number of nuetrons must also be 6.

This doesn't exactly answer the question though. The obvious things that differentiate one atom from another are their atomic number, the number of protons and electrons inside an atom, and their atomic mass.