History, Atomic Structure and Electrons
To understand the atom, you will need to understand its basic structure (what it's made of and how those parts are arranged). One way to approach this topic is to look at it from a historical perspective and to see how our understanding and knowledge was built up.
If you click on the timeline below, you will see a larger version that has active links.
Each GREEN link is a step in out understanding of the basic structure of the atom.
This basic knowledge should allow you to be able to determine the number of protons, electrons and neutrons in an atom, as well as the atomic number, the mass number and the charge. In addition, you should understand the difference between mass number and atomic mass and know how to do calculations involving atomic mass and percent abudance of isotopes.
Each RED link is step to our current understanding of the arrangement of electrons in atoms.
Understanding electrons leads us to electron configuration of both atoms and ions.