1. THIS SERIES OF REACTIONS IS A TRANSMUTATION SERIES, A SERIES OF NUCLEII DECOMPOSE INTO ITHER SPECIES UNTILL A STABLE ISOTOPE IS PRODUCED TO END THE PROCESS. A VARIETY OF RADIATION IS EMITTED.

2. QUESTIONS
#8- WHAT IS THE TIME (h) FOR POTASSIUM-42 TO UNDERGO THREE HALF-LIFE PERIODS? 1
1/2
1ST T
2ND T
1/4
3RD T
1/8
NUMBER OF HALF LIFE PERIODS = t/T
WHERE T = HALF LIFE (TABLE N)
t = TIME ELAPSED
3 = t/ 12.4 h = 37.2h

3. #9 –If a sample of 10 grams decays to 5 grams after 2 days what is the half life?
1/2
1ST T
2ND T
1/4
3RD T
1/8
FRACTION REMAINING = REMAINING/ORIGINAL
5/10 = ½ REMAINING
It takes one half life to get to ½ the original. In this question that is 2 days

4. #10- After 6 days what fraction of an element with a half life 2 days remains.
NUMBER OF HALF LIFE PERIODS = t/T
WHERE T = HALF LIFE (TABLE N)
t = TIME ELAPSED
#T = t/T = 6/2 = 3 1
1/2
1ST T
2ND T
1/4
3RD T
1/8
6 days is 3 half lives and 1/8 of the sample remains,

5. 40g Fraction persist= (1/2)t/T = (1/2)24d/8.07d = 1/8 1/8 of 40 = 5g
#11- How many grams of I-131 will persist after 24 d if 40.0g was present initially.?
Fraction persist= (1/2)t/T = (1/2)24d/8.07d = 1/8
1/8 of 40 = 5g
40g
20g
1ST T
2ND T
10g
3RD T 5g