Download LSHS Graphing Periodic Trends Lab

Activity: Graphing Periodic Trends
PURPOSE: Use the periodic table to identify and explain periodic trends, including atomic and ionic
radii, electronegativity and ionization energy.
DISCUSSION: There are many periodic trends that occur as you cross a period or go down a
group/family on the Periodic Table. Graphing various elemental properties will help to illustrate these
trends.
REFERENCE:
Angstrom - A unit of distance equal to one ten-billionth of a meter.
Atomic Radius - The distance from the center of the nucleus to the valence electron energy level.
Ionic Radius - The distance from the center of the nucleus to the valence electron energy level of the ion.
Ionization energy - The energy required to remove an electron from an atom.
Electronegativity - The energy with which an atom can attract an electron
DATA:
Properties of the First 18 Elements
Atomic
Ionic
Ionization
Atomic
Electronegativity
Element
Radius
Radius
Energy
Number
(Pauling)
(Angstroms) (Angstroms)
(KJ)
H
1
0.79
0.012
314
2.2
He
2
0.49
?
567
?
Li
3
2.05
0.76
124
0.98
Be
4
1.4
0.35
215
1.57
B
5
1.17
0.23
191
2.04
C
6
0.91
0.16
260
2.55
N
7
0.75
0.13
335
3.04
O
8
0.65
1.4
314
3.44
F
9
0.57
1.33
402
4
Ne
10
?
?
?
?
Na
11
2.23
1.02
119
0.93
Mg
12
1.72
0.72
176
1.31
Al
13
1.82
0.535
138
1.61
Si
14
1.46
0.4
188
1.9
P
15
1.23
0.38
242
2.19
S
16
1.09
0.37
239
2.58
Cl
17
0.97
1.81
299
3.16
Ar
18
?
?
?
?
Using the data above, construct the following line graphs: (Give each graph a title and label both the xaxis and the y-axis. Connect your points. Predict the plot points for elements with questions marks.)
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Activity: Graphing Periodic Trends
1. Atomic Radius (y) vs. Atomic Number (x).
2. Ionic Radius (y) vs. Atomic Number (x).
3. Ionization energy (y) vs. Atomic Number (x).
4. Electronegativity (y) vs. Atomic Number (x).
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Activity: Graphing Periodic Trends
Below is a modified periodic table for elements 1-18. Using the data provided above draw Bohr models
for each element that reflect the atomic size of each element. As much as possible try to take into
account the relative size of the nucleus and the electron cloud.
Bohr Models Representing Atomic Size
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
CONCLUSION: Use your graphs to answer the following questions.
Circle the correct answer then explain why it is correct.
1. Radii of the atoms [increase, decrease] as you go across (L to R) a period? Explain why -
2. Radii of the atoms [increase, decrease] as you go down a family? Explain why -
3. The energy needed to remove an electron from an atom generally [increases, decreases] as you go
across a period? Explain why this occurs.
4. Why is the electronegativity of Lithium smaller than the electronegativity of Hydrogen?
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Activity: Graphing Periodic Trends
5. Circle the atom with the largest atomic radius (size) in each group:
a.
b.
c.
d.
aluminum, sulfur, phosphorus
arsenic, bismuth, nitrogen
iron, lithium, silicon
barium, beryllium, bromine
6. Circle the atom that would require the SMALLEST ionic radius in each group:
a.
b.
c.
d.
magnesium, chlorine, silicon
lithium, cesium, potassium
fluorine, iodine, chlorine
calcium, bromine, cobalt
7. Circle the atom that would require the MOST amount of energy to remove an ea.
b.
c.
d.
lithium, potassium, rubidium
sodium, chlorine, silicon
polonium, oxygen, sulfur
fluorine, iodine, chlorine
Circle the correct answer(s) in the brackets below.
8. Going across a period from left to right:
The [ p+, N , e- ] in the nucleus increase, thus pulling the [ p+ , N , e- ] closer towards the center of the
atom and [ increasing, decreasing ] the atomic radii. Because of this increase in electromagnetic, strong
force atoms tend to [ gain, lose] electrons as you go across the periodic table.
9. Going down a metallic family:
The number of [ p+ N e- ] energy levels increases by one, making the atomic radius [ larger, smaller ].
Because the electrons are farther from the nucleus they tend to be [ gained, lost ] more easily. Therefore
metals tend to be [ more, less ] chemically active as you go down a family.
10. Going down a nonmetal family:
The nucleus gets [ closer, farther] from the outer energy level, thereby[ increasing/ decreasing ] the pull
on free electrons from metals. Because of this nonmetals tend to be [ more, less ] chemically active as
you go down a family.
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