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: 11/17 Week 12 Catalyst Chart 66 11/17 Unit 3 Review (do not staple, turning in) 67 11/17 Notes: Calculating Average Atomic Mass 68

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!

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

Let’s take a look at Friday’s data…

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

Calculating Average Atomic Mass Pg68

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 17 17 Chlorine - 35 Chlorine - 37

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?

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

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

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

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

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

Check for Understanding The average atomic mass of Carbon, C, is 12.01 amu. Predict which isotope has the greatest percent abundance based upon the average atomic mass. Carbon – 10 Carbon – 12 Carbon – 13 Carbon -- 14

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

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

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 28.09 is closest to 28.

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

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

Problem #4 Helium has two naturally occurring isotopes, He-3 and He-4. The atomic mass of helium is 4.003 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.