Name ____________________________________________________________________________________ Date ____________
Trends in the Periodic Table
1. Draw a line in the middle of a piece of graph paper, dividing the page into top and bottom. On the top,
plot a graph of ionization energy (y-axis) vs. atomic number (x-axis). On the bottom, plot a separate
graph of atomic radius vs. atomic number. For each graph connect successive dots with straight lines.
Also, ensure that identical atomic numbers are plotted at the same vertical position on the sheet (i.e.
atomic number 1 in the top graph should be on the same line as atomic number 1 in the bottom graph).
Atomic Number
Element Symbol
First Ionization Energy
Atomic Radius
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
H
He
Li
Be
B
C
N
O
F
Ne
Na
Mg
Al
Si
P
S
Cl
Ar
K
Ca
1312
2372
520
899
801
1086
1402
1314
1681
2081
496
738
578
786
1012
1000
1251
1521
419
590
32
31
123
90
82
77
75
73
72
71
154
136
118
111
106
102
99
98
203
174
2. Examine your graph of ionization energy (IE) vs. atomic number.
a. Which elements are found at the main peaks on your graph (there should be 3)? Where are
these elements located on the periodic table in relationship to each other?
b. Which elements are found on the main valleys on your graph (there should be 3)? Where are
these elements located on the periodic table in relationship to each other?
3. Examine your graph of atomic radius vs. atomic number.
a. Which elements are found at the main peaks on your graph? How are these elements located
on the periodic table in relationship to each other?
b. Which elements are found on the main valleys on your graph? How are these elements located
on the periodic table in relationship to each other?
Name ____________________________________________________________________________________ Date ____________
4. How are atomic radii and ionization energy related? (EX: As atomic radius increases, what happens to
the ionization energy?)
5. Generally, as you go from left to right across a period on the periodic table, what happens to atomic
radius? What about ionization energy?
6. Generally, as you go down a group in the periodic table, what happens to atomic radius? What
happens to the ionization energy?
7. What is meant by nuclear shielding? What affect does it have on trends in atomic radii?
8. When Na forms an ion it loses its outer electron and becomes Na+1. What element does Na+1
resemble (with respect to its electron arrangement)? Secondly, which group’s electron configuration do
the alkali metals resemble when they form ions (i.e. lose an outer electron)?
9. What happens to the number of protons in the nucleus as you go across a period? Use this to explain
the trends in atomic radius and ionization energy across a period.
10. Define electronegativity. Where on the periodic table is electronegativity the highest? Explain why
this is the case. (Use your notes!)