Download Chapter 5.3 - Isotopes of Elements

Chapter 5.3 - Isotopes of Elements
Name _________________________________
Date ___________________
Period __________
1. Go to the web address phet.colorado.edu (NO “www”)
2. Click on “Play With Sims”
3. Click on Chemistry on the left side of the page and scroll down to find the Build an Atom simulation.
4. Click Run Now.
2. After the simulation has opened, click the green plus sign next to Symbol, Mass Number, and Net Charge so
that all boxes are maximized.
3. Drag one proton in the center of the diagram where you see the X. Drag one electron toward the center.
4. Draw your diagram in the first box provided below. Use the following legend for drawing protons, electrons
and neutrons for the entire activity.
Legend:
A dark circle for an electron (-)
An open circle for a proton (+)
A lightly shaded circle for a neutron (no charge)
5. In the upper right corner of the box, write the symbol found in the symbol box.
6. Below the diagram, write the mass number found in the mass number box.
7. Drag one neutron towards the center.
8. Draw your diagram in the second box including symbol and mass number.
9. Drag another neutron towards the center.
10. Draw your diagram in the third box including symbol and mass number.
Hydrogen
Hydrogen
H
Mass number ____
Atomic mass 1.0078 amu
Hydrogen
H
H
Mass number ____
Atomic mass 2.0140 amu
Mass number ____
Atomic mass 1.0083 amu
11. Based on your diagrams, what do all hydrogen atoms have in common?
12. What did you notice happen to the atom of hydrogen as more neutrons were added to the nucleus?
13. For the fourth diagram, drag a total of 6 protons, 6 neutrons, and 6 electrons towards the center. Draw and
label everything as you have in the previous boxes.
14. For the fifth diagram, add one more neutron for a total of 6 protons, 7 neutrons, and 6 electrons.
15. For the sixth diagram, add one more neutron for a total of 6 protons, 8 neutrons, and 6 electrons.
Carbon
Carbon
Carbon
C
C
Atomic mass exactly 12 amu
Mass number ____
Atomic mass 13.0034 amu
Mass number ____
C
Mass number ____
Atomic mass 13.0039 amu
Critical Thinking Questions
1. How many protons are found in
a) 12C ______
b) 13C ______
c) 14C ______
2. How many neutrons are found in
a) 12C ______
b) 13C ______
c) 14C ______
3. How many electrons are found in
a) 12C ______
b) 13C ______
c) 14C ______
4. Based on your answers to questions 1-3, what do all carbon atoms have in common?
5. 1H, 2H, and 3H are called isotopes of hydrogen. 12C, 13C, 14C are called isotopes of carbon. Based on your
answers in Critical Thinking Questions 1-3, define what you think the term isotope means.
Isotope: __________________________________________________________________________________
__________________________________________________________________________________________
Exercises
1. Define mass number.
2. Define atomic number.
3. Indicate whether the following statement is true or false and explain your reasoning:
(Use the Periodic Table to help you)
An 18O atom contains the same number of protons, neutrons, and electrons.
6. Complete the following table.
SYMBOL
14
MASS NUMBER
NUMBER OF ELECTRONS
7
16
3
7
3
6
3
30
15
N
19
F
31
P
58
ATOMIC NUMBER
15
Zn
7. List which atoms in the table above are pairs of isotopes?
8. In nature, there are only three isotopes of hydrogen found, 1H, 2H and 3H. There are VERY FEW 3H atoms
found, and absolutely no 4H atoms. Using your observations from step #12, why do you think this is?