1. Monday, November 17th, 2014 HW= Unit 3 Review Problems #1-10
Objective: We will be able to calculate the average atomic mass of an element based on isotope abundance.
Standard: IOD 401
Catalyst: 1. According to Figure 2, which of the following minerals would most typically be found only in rocks of a medium grade?
A. Muscovite
B. Biotite
C. Kyanite
D. Plagioclase
Classroom expectations:
Wear Kenwood ID.
Cell phones, music players, and headphones are put away.
Food is disposed of or put away.
Dressed appropriately.
Notebook is out and you are ready for today’s class.
Table of Contents:
11/ Week 12 Catalyst Chart
11/ Unit 3 Review (do not staple, turning in)
11/ Notes: Calculating Average Atomic Mass

2. Announcements Test NEXT MONDAY!!!
Tutoring Tuesday and Wednesday THIS WEEK!!
NO help from Ms. Ingham THIS THURSDAY!!
There WILL BE a notebook check before Thanksgiving break!

3. Agenda Catalyst/Announcements Homework Check Lab Discussion
Notes: Calculating Average Atomic Mass
Whiteboard Problems

4. Let’s take a look at Friday’s data…

5. Group 1 2 3 4 5 6 7 Small Plain (weighted mass)
Large Plain (weighted mass)
Pretzel (weighted mass)
Average Atomic Mass

6. Calculating Average Atomic Mass
Pg68

7. Isotopes Recall
Atoms with the same number of protons, but different numbers of neutrons.
Atoms of the same element (same atomic number) with different mass numbers
Isotopes of Chlorine
35 Cl 37 Cl
Chlorine Chlorine - 37

8. Isotopes Recall
Despite these differences, isotopes are chemically alike because they have identical numbers of protons and electrons.
Neon-20, neon-21, and neon-22 are three isotopes of neon, a gaseous element used in lighted signs. Comparing and Contrasting How are these isotopes different? How are they similar?

9. Isotopes Recall Isotope Protons Electrons Neutrons Nucleus Hydrogen–1
(protium) 1
Hydrogen-2
(deuterium)
Hydrogen-3
(tritium) 2

10. Review: Check for Understanding
Fluorine has an atomic number of 9. Write out the name of the isotope of fluorine that has 8 neutrons.
Fluorine-17

11. Review: Check for Understanding
Fluorine has an atomic number of 9. Write out the SYMBOL of the isotope of fluorine that has 10 neutrons.
Mass #  19 F
Atomic #  9

12. Review: Check for Understanding
Three isotopes of chromium are chromium-50, chromium-52, and chromium-53. How many neutrons are in each isotope, given that chromium has an atomic number of 24?
Chromium-50:
50-24 = 26 neutrons
Chromium-52:
52-24 = 28 neutrons
Chromium-53:
53-24 = 29 neutrons

13. Average Atomic Mass What is average atomic mass?
Average atomic mass is the weighted average of the atomic masses of the naturally occurring isotopes of an element
The average mass on the periodic table is closest to the ISOTOPE of GREATEST abundance

14. Check for Understanding
The average atomic mass of Carbon, C, is amu. Predict which isotope has the greatest percent abundance based upon the average atomic mass.
Carbon – 10
Carbon – 12
Carbon – 13
Carbon -- 14

15. Whiteboard Practice Show all of your work when completing the problem.
DO NOT hold up your board until told to do so.

16. Problem #1 Write the isotope SYMBOL for the following: Neon -22 Ne
Magnesium-26 Mg 22 10 26 12

17. Problem #2
Silicon has 3 different isotopes: Silicon-28 Silicon-29 Silicon-30 Which isotope is MOST abundant? Explain. Silicon-28 because the average atomic mass of is closest to 28.

18. Problem #3
Determine the number of protons, electrons, and neutrons in the following P = E= N= P = E = N = 12 12 14 10 10 12

19. Problem #4
Determine the protons, neutrons, and electrons in the isotopes of silicon: Silicon-28 P = 14 E = 14 N= 14 Silicon-29 P = 14 E = 14 N = 15 Silicon-30 P = 14 E= 14 N = 16

20. Problem #4
Helium has two naturally occurring isotopes, He-3 and He-4. The atomic mass of helium is amu. Which isotope is more abundant in nature? Explain.
He-4 is more abundant in nature because the atomic mass is closer to the mass of He-4 than to the mass of He-3.