Atoms and the Periodic Table http://learn.genetics.utah. edu/content/cells/scale/ Atomic Theory…So there were these scientists who thought the world was made of things we couldn’t see • The structure of the atom is still being studied-that’s why it’s a theory • Some scientists you may hear about: Democritus, Dalton, Rutherford, Thomson, Bohr, Millikan, Chadwick, Meitner, Schrodinger, Heisenberg, Seaborg, Curie…. ATOMS ARE: • The smallest part of a pure substance you can have that is still that substance • A “pure substance” is made of one type of material (atom) • The building blocks of each of the 118 elements on the periodic table. Each element is made up of their own group of identical atoms. • For example: the element gold (Au) is ONLY made of gold atoms • Able to combine to form larger and more complex substances (we’ll get to them in a bit) • Made of even smaller particles: protons, neutrons, electrons (these are made up of even smaller particles) • Still mysterious!! We don’t know how all the parts work completely ELEMENTS ARE: • Made of atoms • Only breakable into the smaller atoms that make them up • Organized by characteristic properties on THE PERIODIC TABLE OF ELEMENTS • Each element has it’s own box • Each element has numbers and symbols unique to themselves • Natural and man-made • There are 92 naturally occurring elements • There are 26 man-made or synthetic elements-how do we do this? THE PERIODIC TABLE, YOUR NEW BEST FRIEND!! How do we read it? ATOMIC NUMBER: • Elements are organized by it • Will tell you about the particles that make up an atom ATOMIC MASS: • Seems to go in order, but be careful • Will tell you about the particles that make up an atom 2 He Helium 4.0026 SYMBOL • Shorthand way to write element • Very specific in terms of capitalization • Use exactly as portrayed on Periodic Table!!! NAME • What the element is called • Some symbols match the names To be continued…. Up next, organization of periodic table!