Name______________________ Hr __

PURPOSE: To determine how certain properties are periodic when the elements are arranged
in periods or groups.

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.
Ionization energy - The energy required to remove an electron from an atom.

DATA

Properties of the First 18 Elements

1 0.79 314
H
He 2 0.49 567
Li 3 2.05 124
Be 4 1.4 215
B 5 1.17 191
C 6 0.91 260
N 7 0.75 335
O 8 0.65 314
F 9 0.57 402
Ne 10 ? ?
Na 11 2.23 119
Mg 12 1.72 176
Al 13 1.82 138
Si 14 1.46 188
P 15 1.23 242
S 16 1.09 239
Cl 17 0.97 299
Ar 18 ? ?

Using the data above, make a line graph the following data. Draw a dark vertical line to
separate the 3 periods. Give each graph a title and label both the x-axis and the y-axis.
Connect your points. Predict the plot points for elements with questions marks.

1. Atomic Radius (y) vs. Atomic Number (x) for the first 3 periods (18 elements – 3 graphs)

2. Ionization energy (y) vs. Atomic Number (x) for the first 3 periods (18 elements – 3 graphs)
 Properties of the Alkali Metals & Halogens
Atomic Radius
Ionization Energy
Element (Angstroms)
Alkali Metals --- ------
Li 2.05 124
Na 2.23 119
K 2.77 100
Rb 2.98 96
Cs 3.34 90
Fr ? ?
Halogens --- ------
F 0.57 402
Cl 0.97 299
Br 1.12 272
I 1.32 241
At 1.43 ?
Fr & At are extremely rare - they exist only in trace amounts.

Using the data above, graph (line graph) the following data. Use element symbols on x-axis
instead of atomic number. Give each graph a title and label both the x-axis and the y-axis.
Connect your points. Predict the plot points for elements with questions marks.

1. Atomic Radius(y) vs. Alkali Metals(x) arranged in increasing atomic number.

2. Ionization Energy (y) vs. Alkali Metals(x).

3. Atomic Radius(y) vs. Halogens(x).

4. Ionization Energy (y) vs. Halogens(x).

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. What is the relationship between ionization energy and members of:

b. The Halogens:______________________________________________________________

5. Circle the atom with the largest atomic radius (size) in each group:

a. aluminum, sulfur, phosphorus

c. iron, lithium, silicon

d. barium, beryllium, bromine

6. Circle the atom that would require the LEAST amount of energy to remove an e-

a. magnesium, chlorine, silicon

c. fluorine, iodine, chlorine

d. calcium, bromine, cobalt

7. Circle the atom that would require the MOST amount of energy to remove an e-

a. lithium, potassium, rubidium

c. polonium, oxygen, sulfur

d. 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 theytend 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.