1. Oct 17 & Oct 20 QUIZ – LoC List #4  Quiz starts 2 minutes after bell ring  You have 4 minutes!

2. Warm-up#5: Summarize the contributions to the Atomic Theory ScientistExperimental Design Conclusion/ Contribution Hypothesized model Democritus-------------- Niels Bohr-------------- Quiz over history of atomic theory next time!

3. Draw what you think an atom looks like Draw a model of an atom on the front of a sticky note and put your name on the back. Then stick it on the white board. The Atom

4. Reviews of Atoms All matter is made up of elements (e.g. carbon, hydrogen, etc.). The smallest part of an element is called an atom. Atom of different elements contain different numbers of protons The mass of an atom is almost entirely due to the number of protons and neutrons

5. Parts of Atoms - Subatomic Particles Atom consists of two parts:  The nucleus which contains: Protons Neutrons  Orbiting Electrons What are their charges?

6. Ions

7. The Atom (reminder) The atom consists of two parts: 1. The nucleus which contains: 2. Orbiting electrons protons neutrons

8. Ions have charges! Charge: 0+1 Ions’ charges come from changes in ELECTRONS only!

9. Isotopes

10. What is an isotope?  Number of protons for an atom of a specific element never changes.  Number of neutrons can change.  Two atoms with equal protons but different neutrons are called isotopes of each other.  All atoms in existence are isotopes! Some isotopes are just more common than others.

11. Isotopes Atoms with equal protons but different number of neutrons What do you notice that the isotopes have in common? What varies?

12. X A Z Mass number Atomic number Element symbol = number of protons + number of neutrons = number of protons Isotope Notation

13. Write isotope notation for each isotope of hydrogen below:

14. Hyphen Notation Write out the name of the element, then add a hyphen (-), then the mass number. Write the hyphen notation for the three isotopes of hydrogen. Isotope Notation Hyphen Notationhydrogen-1hydrogen-2 hydrogen-3

15. Summary If protons vary, the identity of the element changes oxygen has 8 protons; fluorine has 9 protons If neutrons vary, mass number changes and we have different isotopes sulfur-32 has 16 neutrons; sulfur-33 has 17 neutrons If electrons vary, charge changes and we have different ions iron can lose two electrons to become Fe +2 ; iron can also lose three electrons to form Fe +3 All atoms are isotopes; isotopes can also become ions

16. Petri Dish Atoms Activity Draw a card – same number in same group You will work on 2 petri dishes at a time You must complete the chart for at least 6 petri dishes You will return the pair of petri dishes to the box when you are finished and get 2 new ones. Isotope notation looks like this: K 40 19 Mass number of this atom Atomic number of this atom Symbol of this element Ion charge, if it is not zero +1

17. Homework Quiz: Atomic Theory History—be ready!! Page 4: top half Sapling Practice Assignment due Monday night Sapling #1 due next Friday night