1. Anatomy of an Atom Nucleus – The central part of an atom made up of Protons and Neutrons. Neutron – Particle found in the nucleus which has No Electrical Charge, and a mass about the same size as a Proton. Proton – Particle in the nucleus, which has a Positive Electrical Charge. Electron – Particle that orbits the nucleus of an atom and has a Negative Electrical Charge. They move more rapidly around the outer areas of the atom. Their arrangement determines the chemical properties of an atom.

2. Atoms are made up of pieces particlesymbol “relative” mass “relative” charge location protonp+p+ 1+1nuclear neutronnono 10nuclear electrone-e- negligibleextra nuclear

3. “relative” vs. “absolute” particle “relative” mass “absolute” mass “relative” charge “absolute” charge p+p+ 11.67 x 10 -24 g+1+1.60 x 10 -19 C nono 11.67 x 10 -24 g00 e-e- negligible9.09 x 10 -28 g-1.60 x 10 -19 C

4. The Periodic Table various atoms are arranged on The Periodic Table Over 100 various kinds of building blocks exist

5. Looking at an example we find all sorts of information. 6C Carbon 12.0111 Atomic Number Symbol Atomic Mass

6. Atomic number Atomic number (a.k.a. proton number) Indicates the # of p + ’s an atom has Identification Tag of the element example: each and every C atom has 6 p + ’s 5 p + ’s would make it B 7 p + ’s would make it N

7. Symbol The abbreviated shorthand used to represent a particular atom Rules Atoms are represented by a 1, 2, or in some cases 3 letter Arabic letter code. The 1 st letter is always capitalized; the others (if there are any) are always expressed in the lower case.

8. Be careful using symbols Po  PO

9. Atomic Mass Indicates the amount of matter present in an atom Mass = ( # p + ) + ( # n o ) + (# e - ) But considering the negligible mass of the electron Mass = ( # p + ) + ( # n o )

10. Looking back at the original example: 6C Carbon 12.0111 #charge p+p+ 6+ 6 nono 6 0 e-6- 6 18 0

11. Example #2 47Ag Silver 107.8682 #charge p+p+ 47+ 47 nono 61 0 e-47- 47 155 0

12. Review problem #1 Fill in the chart below 92U Uranium 238.0289 #charge p+p+ nono e-

13. Review problem #2 How many protons are in the following atom? 10Ne Neon 20.1797

14. Review problem #3 How many neutrons are in the following atom? 11Na Sodium 22.98977

15. Review problem #4 How many electrons are in the following “neutral” atom? 3Li Lithium 6.941