1. DAY 5 Chapter 4 Section 2 and 3

2. HOW ATOMS DIFFER Start with some Vocab Atomic Number Atoms total # of Protons Atoms Total # of Electrons Note: as long as the atom is neutral in charge Atomic # identifies an atom of a particular element. It never changes How to read the Periodic Table

3. CHECK Identify the following to fill in the chart. 1. Name of element 2. # of Protons 3. Average Atomic Mass

4. ATOMIC NUMBERS Complete the following table Composition of Several Elements ElementAtomic NumberProtons Electro ns a.Pb82 b.8 c.30 82 Zn30 8 8 O

5. ISOTOPES AND MASS NUMBER What do we know…? Does the # of protons of an element ever Change? NO Does the # of electrons of an element ever change? NO What’s Left? # of Neutrons will change What does this mean? Atoms with the same number of protons but different number of neutrons are called isotopes.

6. THE MASS NUMBER So…The Mass Number is… (Atomic #) + (# of neutrons) What makes up the mass number of an isotope. Remember Relative Mass Protons = 1amu Neutrons = 1amu What’s this mean? If an element has 1 proton and 1 neutron what's the Mass Number? 2

7. WHAT DOES ALL THIS MEAN? Elements have different forms in nature Lets look at Copper… How many protons in Copper? 29 protons Does this ever change? No But copper has two forms with different mass numbers. What changes…# of Protons or # of Neutrons? # of neutrons

8. COPPER - ISOTOPES Copper – 63 Copper - 65 Other ways to write it Mass number Cu 65 29 Cu 63 29 Other ways to write it

9. LEARNING CHECK 1 st … J.J. Thomson The Plum pudding Model…didn’t last long We know…Atoms are neutral / no charge (positives cancel negatives) Proposed…Uniformly (evenly) distributed positive and negative charges.

10. NATURAL ABUNDANCE % abundance

11. LET’S PROVE THE NUCLEUS Didn’t happen… The alpha particles (positive charge) bounced all over the place…Why?

12. LET’S PROVE THE NUCLEUS The Protons have a positive charge…repelled the positive alpha particle The neutron has no charge doesn’t effect it.

13. THE MASS OF THE ATOM What does relative mean? Comparative / in proportion to something So…whats 1.67x10 -27 = 1 (relative)

14. THE MASS OF THE ATOM What does relative mean? Comparative / in proportion to something

15. ONE LAST NOTE Quarks? And plasm? Parts that make up Protons and neutrons Scientists don’t know their effect on chemical behavior

16. HOMEWORK ASSIGNMENT Moodle Assignment Day 5

17. A LOOK AHEAD Day 6: Isotope Lab / Quiz on the Atom Day 7: Chapter 4 Section ¾ Day 8: Isotopes Quiz: Chapter 24 Section 1 Day 9: Chapter 24 Section 2