On a sheet of loose leaf, write down the SPARK On a sheet of loose leaf, write down the following: What fraction of the original sample is remaining after one HALF life? What fraction of the original sample is remaining after TWO half lives? What is the half life of Carbon-14 (HINT: use your reference table N) AGENDA 1) SPARK 2) SHARE OUT 3) LESSON 4) CLASS WORK 5) WRAP UP

SPARK Half Lives Passed Fraction Remaining 1 1/2 2 1/4 3 1/8 4 1/16 5 Regents Chemistry Unit: 4 SPARK Can we make a chart to represent half life? Half Lives Passed Fraction Remaining 1 1/2 2 1/4 3 1/8 4 1/16 5 1/32 AGENDA 1) SPARK 2) SHARE OUT 3) LESSON 4) CLASS WORK 5) WRAP UP

LET’S MAKE THIS VERY SIMPLE What fraction of a sample of gold-198 remains radioactive after 2.69 days? a) ¼ c) ¾ b) ½ d) 7/8 Now we could use some crazy math equations to solve this problem… instead let’s use the chart we made at the beginning of class and reference Table N AGENDA 1) SPARK 2) SHARE OUT 3) LESSON 4) CLASS WORK 5) WRAP UP

LET’S PRACTICE TOGETHER 1. How much of a 100-mg sample of nitrogen-16 will remain after 28.8 seconds of decay? Step 1: write down what you know… Started with 100 mg of N-16 Total time elapsed = 28.8 sec Step 2: write down what you WANT to know… How much is left? Step 3: find more information… What is the half life of nitrogen 16? Step 4: use the chart AGENDA 1) SPARK 2) SHARE OUT 3) LESSON 4) CLASS WORK 5) WRAP UP

LET’S PRACTICE TOGETHER 1. After 62.0 hours, 1.0 gram remains unchanged from a sample of 42K. What is the total number of half life periods? How much 42K was in the original sample? Step 1: write down what you know… Step 2: write down what you WANT to know… Step 3: find more information… Step 4: use the chart AGENDA 1) SPARK 2) SHARE OUT 3) LESSON 4) CLASS WORK 5) WRAP UP

LET’S PRACTICE TOGETHER 1. How many half-lives are required for radioisotope to decay to 1/32 of its initial value? AGENDA 1) SPARK 2) SHARE OUT 3) LESSON 4) CLASS WORK 5) WRAP UP

LET’S PRACTICE TOGETHER Manganese-56 is a beta emitter with a half-life of 2.6 h. What is the mass of manganese-56 in a 1.0- mg sample of the isotope at the end of 10.4 h? AGENDA 1) SPARK 2) SHARE OUT 3) LESSON 4) CLASS WORK 5) WRAP UP

YOUR TURN: YOU MAY TALK TO YOUR NEIGHBOR How many half-life periods have passed if 80 grams of C-14 has decayed to 5 grams? Use Table N to determine the half-life of C-14. Determine the amount of time that has elapsed as C-14 decays from 80 g to 5 g. 1. 2. 3. AGENDA 1) SPARK 2) SHARE OUT 3) LESSON 4) CLASS WORK 5) WRAP UP

PUSH IT Part 1: Identify the pattern in the following nuclear Regents Chemistry Unit: 4 PUSH IT Part 1: Identify the pattern in the following nuclear equation. 1 9 6 4 1H + 4Be  3Li + 2He 1. Part 2: Use the pattern to write the missing number into the different nuclear equation written below. 27 13Al + 2He  15P +0n 4 30 Part 3: In a few short sentences, describe how you came up with your answer to part 2. AGENDA 1) SPARK 2) SHARE OUT 3) LESSON 4) CLASS WORK 5) WRAP UP