1. First Sci-Fi Movie Released (1902) Read for Thursday Read for Thursday Chapter 3: Sections 3-4 Chapter 3: Sections 3-4 HOMEWORK – DUE Thursday 9/3/15 HOMEWORK – DUE Thursday 9/3/15 HW-BW 2 (Homework Bookwork) #’s 1-7 all, 14, 19, 21, 23, 36, 47-50 all, 57, 59-66 all, 81, 82, 113, 114, 116, 127, 132 HW-BW 2 (Homework Bookwork) #’s 1-7 all, 14, 19, 21, 23, 36, 47-50 all, 57, 59-66 all, 81, 82, 113, 114, 116, 127, 132 HW-WS 2 (Homework Worksheet) (from course website) HW-WS 2 (Homework Worksheet) (from course website) HOMEWORK – DUE Tuesday 9/8/15 HOMEWORK – DUE Tuesday 9/8/15 HW-BW 3.1 (Bookwork) CH 3 #’s 3, 4, 11-24 all, 26, 27 HW-BW 3.1 (Bookwork) CH 3 #’s 3, 4, 11-24 all, 26, 27 HW-WS 3 (Worksheet) (from course website) HW-WS 3 (Worksheet) (from course website) HOMEWORK – DUE Thursday 9/10/15 HOMEWORK – DUE Thursday 9/10/15 HW-BW 3.2 (Bookwork) CH 3 #’s 41, 45, 48, 56-61 all, 68, 70, 72, 73, 78, 79, 85, 88, 95, 96, 104, 119, 124 HW-BW 3.2 (Bookwork) CH 3 #’s 41, 45, 48, 56-61 all, 68, 70, 72, 73, 78, 79, 85, 88, 95, 96, 104, 119, 124 HW-WS 4 (Worksheet) (from course website) HW-WS 4 (Worksheet) (from course website) Lab Wednesday/Thursday Lab Wednesday/Thursday EXP #2- PRELAB!!!! EXP #2- PRELAB!!!!

2. Atoms vs. Ions Atoms can gain or lose e - to form IONS Atoms can gain or lose e - to form IONS ANY charged particle is called an ANY charged particle is called an ion Losing e - gives charge Losing e - gives POSITIVELY charge Called Called cations Usually formed from metals Usually formed from metals Gaining e - gives a charged ion Gaining e - gives a NEGATIVELY charged ion

3. 16 e - = Charge!!! When an atom GAINS electrons S S  S 2- S  S 2- + 2e- BeforeAfter S S + 2e -  S + 2e -  S 2- WRONG!! 18 e - = 18 e – 16 p + = 16 p + – –2

4. Atoms vs. Ions Atoms can gain or lose e - to form IONS Atoms can gain or lose e - to form IONS ANY charged particle is called an ANY charged particle is called an ion Losing e - gives charge Losing e - gives POSITIVELY charge Called Called cations Usually formed from metals Usually formed from metals Gaining e - gives a charged ion Gaining e - gives a NEGATIVELY charged ion Called Called anions Usually formed from non-metals Usually formed from non-metals

5. My Atom Broke Subatomic Particles Subatomic Particles Nucleus Nucleus Neutrons – n o Neutrons – n o No charge No charge # can vary from atom to atom # can vary from atom to atom

8. Mass of n o about equal to mass of p + Do each of these atoms have the same mass? Isotopes: Atoms having the same atomic number, but different atomic masses

9. Atomic symbols E A Z Symbol of element Atomic number Mass number= # p + + # n o S 16

10. 32 16 A Z S E 32 16 S 33 16 S 34 16 S 36 16 S Shorthand: Sulfur-33 S-36 36 S

11. Give the atom notation for the following: 1) an atom with 82 p + and 126 n o 2) an atom of iron with 28 n o and 26 e - 3) an atom of element 29 having 34 n o and 27 e - 208 82 Pb 54 26 Fe 63 29 Cu 82 p + + 126 n o = +2

12. Information from the Periodic Table = 40.08 amu (atomic mass) = 16.00 amu (atomic mass) (atomic number) 20 = (atomic number) 8 =

13. Atomic Masses Measured in the unit amu Stands for atomic mass unit Defined as 1/12 th the mass of a 12 C atom 35 Cl = 34.9689 amu 50 V = 49.9472 amu 79 Br = 78.9183 amu Are these what the P.T. say?

14. All Isotopes are NOT Created Equal Weighted averages Weighted averages

15. All Isotopes are NOT Created Equal Atomic mass is a WEIGHTED average of isotopes HUH?? FinalQuiz 30020 Possible You earned 2855 average = (93.75%)(6.25%) (score 1 x weight 1 ) + (score 2 x weight 2 ) = grade (285 (285 x 0.9375) (285 x 0.9375) + (5 (285 x 0.9375) + (5 x 0.0625) = (285 x 0.9375) + (5 x 0.0625) = 267.5

16. All Isotopes are NOT Created Equal Weighted averages Weighted averages An equation (oh crap) An equation (oh crap) 35 Cl = 34.9689 amu 35 Cl = 34.9689 amu Abundance = 75.77% Abundance = 75.77% 37 Cl = 36.9659 amu 37 Cl = 36.9659 amu Abundance = 24.23% Abundance = 24.23% These must be the only 2 isotopes... Why? These must be the only 2 isotopes... Why?

17. 35 Cl = 34.9689 amu Abundance = 75.77% 37 Cl = 36.9659 amu Abundance = 24.23% 34.9689 x 0.7577 + 36.9659 x 0.2423= 35.45amu Where have I seen this before? Periodic Table gives AVERAGE ATOMIC MASS in amu!! =0.7577 =0.2423 All Isotopes are NOT Created Equal

18. 78.90% of all magnesium is 24 Mg  23.985 amu 10.00% of all magnesium is 25 Mg  24.986 amu 11.10% of all magnesium is 26 Mg  25.983 amu 11.10% 100.00% = 24.30 amu A Problem! What is the average atomic mass of magnesium?

19. Some Algebra and a New Equation decimal, not % (i.e. 0.1234 not 12.34%) For solving for % abundance multiply by 100 to get percentages

20. DO NOT use “normal” averages DO NOT use “normal” averages If asked for two percent-abundances, use: If asked for two percent-abundances, use: If asked for ANYTHING else: If asked for ANYTHING else: Isotopes Calculation Summary

21. Another Problem! Lead has 4 isotopes, the masses and abundances of which can be found in the following table. Your job? Calculate the isotope mass of lead-207. lead-204 203.973 amu 1.40% lead-206 205.974 amu 24.10% lead-207???? lead-208 207.977 amu 52.40% ???? 22.10% X = Lead-207 = 206.9 amu

22. A Problem! Thallium has 2 isotopes, and. has a mass of 202.973 amu and has a mass of 204.974 amu. What are the percent abundances of each of the isotopes?  Abundance 1 = 30.2%  Abundance 2 = 69.8%

23. A Problem! Bromine has 2 isotopes, and. has a mass of 78.9193 amu and has a mass of 80.9163 amu. What are the percent abundances of each of the isotopes?  Abundance 1 = 50.44%  Abundance 2 = 49.56%

24. Percent Composition How much of each element makes up a compound