Name: Date:
Student Exploration: Periodic Trends.
Vocabulary: atomic radius, electron affinity, electron cloud, energy level, group, ion, ionization
energy, metal, nonmetal, nucleus, period, periodic trends, picometer, valence electron
Prior Knowledge Questions (Do these BEFORE using
the Gizmo.)
1. On the image at right, the two magnets are the same.
Which paper clip would be harder to remove? B
2. Which magnet would be most likely to attract additional paper clips? B
3. What is the relationship between the thickness of the book and the ability of the magnet to
hold on to and attract paper clips? I infer that the thicker the book is the harder its going to
be for the magnet to attract paper clips. I think because the smaller book has the magnet
closer it would have a stronger range force.
Gizmo Warm-up
Just as the thickness of a book changes how strongly a magnet attracts a
paper clip, the size of an atom determines how strongly the nucleus
attracts electrons. In the Periodic Trends Gizmo, you will explore this
relationship and how it affects the properties of different elements.
The atomic radius is a measure of the size of the electron cloud, or the region where
electrons can be found. To begin, check that H (hydrogen) is selected in Group 1 on the left.
Turn on Show ruler. To measure the radius, drag one end of the ruler to the proton in the
nucleus and the other end to the electron. Click Save radius to record the value.
1. What is the radius of hydrogen? 53pm
Notice that the radius is measured in picometers (pm). A picometer is one trillionth of a
meter.
2. On the right side of the Gizmo, select Li. Connect the right side of the ruler to the outermost
electron, or valence electron. What is the radius of lithium? 167pm
This study source was downloaded by 100000842568006 from CourseHero.com on 05-06-2022 14:08:26 GMT -05:00
2018
https://www.coursehero.com/file/63520801/PeriodicTrendsSEdocx/
, Get the Gizmo ready:
Activity A:
Check that Atomic radius is selected from the
Atomic radius
drop-down menu.
Question: What factors affect the radius of an atom?
1. Predict: How do you think the radius of an atom will change as you move down a group
(vertical column) in the periodic table? It increases as you move down the periodic table.
2. Collect data: Use the ruler to measure the atomic radii of the group 1 elements. As you do
so, count the energy levels (shown as rings of electrons) in each atom. Record in the table.
Element H Li Na K Rb Cs
Number of energy levels 1 2 3 4 5 6
Atomic radius (pm) 53 167 190 243 265 298
3. Observe: What happens to the radius as you move down group 1? It increases by 53
4. Explore: Turn off Show ruler. Select Li, and then select Be. Observe the radii of the
elements in group 2. Then look at other groups. What pattern do you see? As the periodic
number increases, the number of electrons increased.
5. Draw a conclusion: In general, what is the effect of the number of energy levels on the
radius of an atom? The radius is slightly less when there is more energy levels
6. Predict: How do you think the radius of an atom will change as you move across a period
(horizontal row) in the periodic table? I believe that the atomic radius as you travel across
the period will decrease.
7. Collect data: Beginning with Na, record the number of energy levels, number of protons, and
atomic radius for each element in period 3.
Element Na Mg Al Si P S Cl Ar
Number of energy levels
Number of protons
Atomic radius (pm)
(Activity A continued on next page)
This study source was downloaded by 100000842568006 from CourseHero.com on 05-06-2022 14:08:26 GMT -05:00
2018
https://www.coursehero.com/file/63520801/PeriodicTrendsSEdocx/
Student Exploration: Periodic Trends.
Vocabulary: atomic radius, electron affinity, electron cloud, energy level, group, ion, ionization
energy, metal, nonmetal, nucleus, period, periodic trends, picometer, valence electron
Prior Knowledge Questions (Do these BEFORE using
the Gizmo.)
1. On the image at right, the two magnets are the same.
Which paper clip would be harder to remove? B
2. Which magnet would be most likely to attract additional paper clips? B
3. What is the relationship between the thickness of the book and the ability of the magnet to
hold on to and attract paper clips? I infer that the thicker the book is the harder its going to
be for the magnet to attract paper clips. I think because the smaller book has the magnet
closer it would have a stronger range force.
Gizmo Warm-up
Just as the thickness of a book changes how strongly a magnet attracts a
paper clip, the size of an atom determines how strongly the nucleus
attracts electrons. In the Periodic Trends Gizmo, you will explore this
relationship and how it affects the properties of different elements.
The atomic radius is a measure of the size of the electron cloud, or the region where
electrons can be found. To begin, check that H (hydrogen) is selected in Group 1 on the left.
Turn on Show ruler. To measure the radius, drag one end of the ruler to the proton in the
nucleus and the other end to the electron. Click Save radius to record the value.
1. What is the radius of hydrogen? 53pm
Notice that the radius is measured in picometers (pm). A picometer is one trillionth of a
meter.
2. On the right side of the Gizmo, select Li. Connect the right side of the ruler to the outermost
electron, or valence electron. What is the radius of lithium? 167pm
This study source was downloaded by 100000842568006 from CourseHero.com on 05-06-2022 14:08:26 GMT -05:00
2018
https://www.coursehero.com/file/63520801/PeriodicTrendsSEdocx/
, Get the Gizmo ready:
Activity A:
Check that Atomic radius is selected from the
Atomic radius
drop-down menu.
Question: What factors affect the radius of an atom?
1. Predict: How do you think the radius of an atom will change as you move down a group
(vertical column) in the periodic table? It increases as you move down the periodic table.
2. Collect data: Use the ruler to measure the atomic radii of the group 1 elements. As you do
so, count the energy levels (shown as rings of electrons) in each atom. Record in the table.
Element H Li Na K Rb Cs
Number of energy levels 1 2 3 4 5 6
Atomic radius (pm) 53 167 190 243 265 298
3. Observe: What happens to the radius as you move down group 1? It increases by 53
4. Explore: Turn off Show ruler. Select Li, and then select Be. Observe the radii of the
elements in group 2. Then look at other groups. What pattern do you see? As the periodic
number increases, the number of electrons increased.
5. Draw a conclusion: In general, what is the effect of the number of energy levels on the
radius of an atom? The radius is slightly less when there is more energy levels
6. Predict: How do you think the radius of an atom will change as you move across a period
(horizontal row) in the periodic table? I believe that the atomic radius as you travel across
the period will decrease.
7. Collect data: Beginning with Na, record the number of energy levels, number of protons, and
atomic radius for each element in period 3.
Element Na Mg Al Si P S Cl Ar
Number of energy levels
Number of protons
Atomic radius (pm)
(Activity A continued on next page)
This study source was downloaded by 100000842568006 from CourseHero.com on 05-06-2022 14:08:26 GMT -05:00
2018
https://www.coursehero.com/file/63520801/PeriodicTrendsSEdocx/
