Elements & Periodic Table
Now we're getting to the heart and soul of the way the Universe works. You know that a generic atom has some protons and neutrons in the nucleus and some electrons zipping around in orbitals. When those pieces start combining in specific numbers, you can build atoms with recognizable traits. If you have eight protons, neutrons and electrons, you will have an oxygen (O) atom. Remember that 'atom' is the general term. As far as we know, there are a limited number of basic elements. With the tools you learn here, you can explore and understand the Universe. Since the launch of the site, we've been asked, "Why start with 18?" (1) Electrons fit nicely into three orbitals. As we move past the first eighteen elements, you can start to learn about transition elements in the fourth period (row) of the periodic table.
Related: Internet Resources on the Periodic Table