1. Chemistry Review Atoms, elements & Isotopes

2. How Big is an Atom?

3. How Many Cuts? Cut 114.0 cm5.5"Child's hand, pockets Cut 27.0 cm2.75"Fingers, ears, toes Cut 33.5 cm1.38"Watch, mushroom, eye Cut 41.75 cm.69"Keyboard keys, rings, insects Cut 6.44 cm.17"Poppy seeds Cut 81 mm.04"Thread. Congratulations if your still in! Cut 10.25 mm.01"Still cutting? Most have quit by now Cut 12.06 mm.002"Microscopic range, human hair Cut 14.015 mm.006"Width of paper, microchip components Cut 181 micron.0004"Water purification openings, bacteria Cut 19.5 micron.000018"Visible light waves Cut 24.015 micron.0000006"Electron microscope range, membranes Cut 31.0001 micron.0000000045"The size of an Atom!

4. I.Atoms A. the basic unit of matter B. matter is anything that takes up space and has mass C. all things are made of atoms D. microscopic … need special microscope to view 1. 100 million atoms lined up in a row would only measure 1 cm long

5. E. Atomic Structure/components 1. Subatomic particles: a. protons 1- positive charge 2- mass weight 1.0073 b. neutrons 1- no charge 2- mass weight 1.0087 c. electrons 1- negative charge 2- mass weight 0.000549 All atoms have the same amt of protons and electrons Atomic number - # of protons Atomic Mass - #p + #n

6. You can see an atom with your eyes? 1. True 2. False Countdown 10

7. An atom has weight 1. True 2. False Countdown 10

8. Which subatomic particle is located outside the nucleus of an atom? 1. Electron 2. Neutron 3. Proton Countdown 10

9. The positively charged particle in an atom the Countdown 10 1. Electron 2. Neutron 3. Proton

10. Protons and ______ are found inside the nucleus. 1. Electrons 2. Neutrons 3. Protons Countdown 10

11. The negatively charged particle in the atom is the 1. Electron 2. Proton 3. Neutron Countdown 10

12. Which combination of particle and charge is correct? Countdown 10 1. Proton: negative charge 2. Electron: positive charge 3. Neutron: negative charge 4. Neutron: no charge

13. II. Elements & Isotopes A. Element is a substance that cannot be broken down B. Elements are made up of lots and lots of the same kind of atom C. more than 100 elements known 1. represents with a single or 2 letters D. only about 2 dozen in living organisms 1. examples – Ca, O, H, C, N, P, K, S, Na, Li, Zn, Mg, Cu, Fe, Se, I, F Co, Al, Si, Br, Ar, Mn, Sr, Pb, V E. Essential Elements of Life: C H N O P S Ca K

14. F. Isotopes 1. atoms of the same element that have differ masses due to the differ number of neutrons on the nucleus a. example: Carbon -12 ; Carbon -13; Carbon – 14 b. all isotopes have the same chemical properties

15. G. Radioactive Isotopes 1. isotopes that give off radioactivity and have unstable nuclei 2. these isotopes break down at a consist rate after a period of time 3. although very dangerous, can be helpful a. Aging Fossils/Rocks b. Treat cancer c. Radioactive “tags” – trace substances d. PET scan (CT scan)

16. III. Compounds A. a substance made of 2 or more elements 1. example – H2O B. held together by chemical bonds C. main types: - ionic - covalent bond - hydrogen - van der waals

17. Isotopes weight the same. 1. True 2. False Countdown 10

18. Radioactive isotopes are good 1. True 2. False Countdown 10

19. Two or more different atoms are combined to form a 1. Symbol 2. Element 3. Isotope 4. Compound Countdown 10

20. In which if the following way do isotopes of the same element differ? Countdown 10 1. In number of neutrons only 2. In number of protons only 3. In number of protons & mass 4. In number of neutrons & mass

21. D. Ionic bonds 1. formed when 1 or more electrons are transferred from 1 atom to another a. opposite charges attract to form an ionic bond (Na(+)) (Cl(-)) b. when atoms lose electrons, the atoms becomes positive c. when atoms gain electrons, they become negative 2. when an atom becomes positively or negatively charged, they become known as ions a. if positively charged known as cation b. if negatively charged known as anion

22. E. Covalent bonds 1. forms when electrons are shared between atoms 2. Two types a. polar covalent 1- unequal sharing due to size differences 2- example: H 2 O b. nonpolar covalent 1- equal sharing of electrons

23. F. Hydrogen Bonds Hydrogen bond is the weak attraction between δ + of H and δ- of O or N of a different molecule

24. G. Van der Waals Interactions 1. Electrons move creating weak positive and negatively charged regions (even if non- polar) 2. named after the scientist 3. can hold even large molecules together 4. geckos show this force a. climbing up the smoothest surface, geckos can hold on even with 1 toe b. a gecko foot is covered w/ half million projections

25. c. the projections are dived into 100s of tiny flat fibers designed to come onto contact with a surface at the molecular level d. van der waals forces form btwn the surface molecules and the gecko foot e. when a gecko wants to move it peels its foot off at angle then reapplies it elsewhere on the surface

26. A covalent bond is formed by 1. Transferring of electrons 2. Sharing electrons 3. Losing electrons 4. Gaining electrons Countdown 10

27. Ionic bonds are formed when 1. Transferring of electrons 2. Sharing electrons 3. Losing electrons 4. Gaining electrons Countdown 10

28. The gecko is an example of Countdown 10 1. Covalent bonds 2. Ionic bonds 3. Hydrogen bonds 4. Van der Waals forces

29. When an atom loses electrons it becomes a ______ ion Countdown 10 1. Positively charge 2. Negatively charged 3. Neutral

30. There are three types of covalent bonds 1. True 2. False Countdown 10

31. Polar covalent is the unequal sharing of electrons 1. True 2. False

32. IV. Representing Atoms A. Bohr Model (e cloud) 1. Use element or # protons/neutrons in nucleus 2. Surrounding by energy shells w/e a. 2 electrons in first shell b. 8 electrons in 2 nd c. 18 electrons in 3 rd shells

33. B. Lewis Dot Structures 1. Use element symbol 2. Use dots to represent 3. valence electrons only

34. The Bohr Model shows how many electrons the element has 1. True 2. False Countdown 10

35. The Lewis dot model shows all electrons an element has 1. True 2. False Countdown 10

36. Questions ASSIGNMENT: Review questions