1. What is an atom??? An atom is the smallest particle of an element that retains its identity in a chemical reaction.

2. What are the parts of the atom??? 1.) Protons 2.) Neutrons 3.) Electrons Positively charged!! Neutral Negatively charged

3. What information do we get about an atom from the Periodic Table of Elements? Mass number = # of protons + # of neutrons Atomic number = # of protons (ID # of an element) # of protons = # of electrons Electron configuration How many electrons can you count?? # of protons = # of electrons

4. Where are protons, neutrons, & electrons located in an atom? John Dalton’s Model of the Atom: Atoms are tiny, indestructible particles, with no internal structure.

5. J. J. Thomson’s Model of the Atom: Plum Pudding Model

6. Ernest Rutherford’s Model of the Atom: Rutherford’s Gold Foil Experiment

7. Ernest Rutherford’s Model of the Atom: The nucleus is the tiny, central core of the atom…contains protons & neutrons The electrons are distributed around the nucleus and occupy most of the volume of the atom.

8. Niels Bohr’s Model of the Atom: Planetary Model of the Atom Electrons move in circular orbits at fixed distances from the nucleus.

9. Given: Mass # = 43 # of electrons = 21 a.) How many protons does this atom have? # protons = # of electrons b.) What is the identity of this atom? # of protons = atomic # c.) How many neutrons does this atom have? mass # = # protons + # neutrons