GRAPHING PERIODIC TRENDS
Standard: SC4. Students will use the organization of the Periodic Table to predict properties of
elements.
a. Use the Periodic Table to predict periodic trends including atomic radii, ionic radii,
ionization energy, and electronegativity of various elements.
Background Information: The periodic table is arranged according to the periodic law which
states that when elements are arranged in order of increasing atomic number, their physical
and chemical properties show a repeating pattern. The properties that will be examined in this
activity are atomic radius (atomic size), ionization energy, and electronegativity.
Purpose: To understand the periodic trends for elements’ atomic radius (size), ionization
energy, and electronegativity
Materials: graph paper, ipad, internet, colored pencils
Pre Lab Questions:
1.
2.
3.
4.
What does the periodic law say?
What does the word “periodic” mean?
Define atomic radius, ionization energy, electronegativity, and electron affinity.
What generally happens to the value of ionization energy as you keep removing more
and more successive electrons from an atom?
5. What group or family of elements has the lowest ionization energy?
6. What element has the highest electronegativity?
1st Data Table: TRENDS DOWN A FAMILY OR GROUP
Element
Atomic Number
Atomic Radius
(in picometers)
H
Li
Na
K
Rb
Cs
1
3
11
19
37
55
31
128
166
203
220
244
First Ionization
energy (in
kilojoules/mole)
1312
520
496
410
403
376
Electronegativity
(on a 4 pt. scale)
2.1
1.0
0.9
0.8
0.8
0.7
2nd Data Table:
TRENDS ACROSS A PERIOD OR SERIES
Element
Atomic number
Atomic Radius
(in picometers)
Na
Mg
Al
Si
P
S
Cl
11
12
13
14
15
16
17
166
141
121
111
107
105
102
First Ionization
energy (in
kilojoules/mole)
496
738
578
787
1012
1000
1251
Electronegativity
(on a 4 pt. scale)
0.9
1.2
1.5
1.8
2.1
2.5
3.0
Procedure:
1. Using the graph paper provided by your teacher, graph the FIRST data table. Give
the graph a correct title AND label the x axis “atomic number” vs. the y axis
“periodic property”. Divide the graph paper into 3 sections: 1st section will be for
atomic number vs. atomic radius (use a blue line for this section); the 2nd section will
be for atomic number vs. first ionization energy (use a red line for this section); the
3rd section will be for atomic number vs. electronegativity (use a green line for this
section).
2. Using the graph paper provided by your teacher, graph the SECOND data table. Give
the graph a correct title AND label the x axis “atomic number” vs. the y axis
“periodic property”. Divide the graph paper into 3 sections: 1st section will be for
atomic number vs. atomic radius (use a blue line for this section); the 2nd section
will be for atomic number vs. first ionization energy (use a red line for this section);
the 3rd section will be for atomic number vs. electronegativity (use a green line for
this section).
Conclusions:
1. In general, what happens to atomic radius (atomic size) as you go down a group or
family?
2. In general, what happens to ionization energy as you go down a group or family?
3. In general, what happens to electronegativity as you go down a group or family?
4. In general, what happens to atomic radius (atomic size) as you go across a period or
series?
5. In general, what happens to ionization energy as you go across a period or series?
6. In general, what happens to electronegativity as you go across a period or series?