Elements, Radioactivity, And The Periodic Table Worksheets With Answer Key, 2015
ADVERTISEMENT
1
2
3
4
5
65/17/2015
Review Topic 3: Elements, Radioactivity, and the Periodic Table
Name:
Score: 19 / 19 points (100%)
Review Topic 3: Elements, Radioactivity, and the Periodic Table
Multiple Choice
Identify the choice that best completes the statement or answers the question.
A 1. The element chlorine exists as two naturally occurring isotopes. Cl35 occurs 75% of the
time and Cl37 occurs 25% of the time. Which of the following calculations should be used
to calculate the correct average atomic mass of chlorine?
a. (35 amu x 0.75) + (37 amu x 0.25)
c. (35 amu x 3) + 37 amu
3
b. (35 amu x 3) + 37 amu
d. 35 amu 37 amu
2
2
ANSWER: A
We learned each amu x %, add them together then divide by 100. The correct
answer here just divided each percent by 100 first.
POINTS: 1 / 1
B 2. Radioactive iodine131 has a halflife of eight days. The amount of a 200.0 gram sample
left after 32 days would be —
a.
c.
6.25 g
25.0 g
b.
d.
12.5 g
50.0 g
ANSWER: B
Total time = # x half life time
32 = # x 8
# = 4, so we need to divide 200.0 grams by 2 four times.
200/2/2/2/2 = 12.5
POINTS: 1 / 1
A 3. Which of these describes a tendency for atomic radii as displayed on the periodic chart?
a.
Atomic radii decrease left to right across a period.
b.
Atomic radii increase left to right across a period.
c.
Atomic radii decrease top to bottom down a group.
d.
Atomic radii increase, then decrease from top to bottom down a group.
ANSWER: A
radii gets bigger going down and smaller going across (left to right), so Fr is
biggest and F is smallest. (Opposite trend of electronegativity)
POINTS: 1 / 1
C 4. How does the radioactive isotope C14 differ from its stable counterpart C12?
a.
It has a different number of protons and two less neutrons than C12.
b.
It has the same number of protons and two more electrons than C12.
c.
It has the same number of protons but two more neutrons than C12.
d.
It has a different number of protons and two more neutrons than C12.
file:///C:/Users/Joseph%20Morris/Desktop/SOL%20Review%20Topics/Review%20Topic%203/review_topic_3_sg.htm
1/6
ADVERTISEMENT
0 votes
Related Articles
Related forms
Related Categories
Parent category: Education