Physics 7
Activity 6: Density and the Periodic Table
I. Density of Air
With this experiment, we will see that even gases have weight! For example in this room right
now there are about 1000 pounds of air! About 15 pounds of air is sitting on each square inch of
your body right now. We will find the density (kilograms per cubic meter) of the air that
surrounds us.
mass of container (valve open) =
gm (to 2 decimal places)
mass of container (evacuated) =
gm (to 2 decimal places)
mass of air in container =
gm =
kg
dimensions of container:
diameter D =
cm,
height H =
cm
Volume of container = HD2
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Show your work and calculations for finding volume here...
Volume of container = ____________________cm3
Now subtract the volume of the base by using water displacement.
Volume of base = ______________cm3
Volume of air = _______________cm3 = _____________m3
(remember...a cubic meter is 100 cm on each side)
Density of air = ________________kg/m3(should be about 1 kg/m^3)
Show calculations for finding density here...
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II. The Periodic Chart
One of the most beautiful and simple patterns in nature is the fact that the world and everything
in it is made up of only a few "building blocks" called ELEMENTS. In the second part of this
activity we will study these building blocks, and use them to construct COMPOUNDS.
The Periodic Chart is an eloquent record that shows us which elements exists, and how these
elements can combine to produce bananas, Corvettes, your sweety, and everything else.
In the table below, choose an element from each group listed in the periodic table that you were
issued in class. Note the rules shown below the table and that the classification refers to a metal,
non-metal, noble gas etc.
Group
1A
2A
3A
6A
7A
8A
Symbol
# of outer e
Gain or lose*
How many?
Class
Valence**
*...for 3 or fewer outer electrons, atom loses all!
for 5 or more outer electrons, atom gains to make 8!
**...valence is charge on atom after outer electrons have been gained or lost.
III. Predicting the way Atoms Combine
Use the Periodic Table, and the rule that electrons lost by one element must be gained by another
element to answer these questions:
A. Sodium and chlorine combine to form a compound, whose common name is salt, with
chemical formula________.
Now write the chemical formulas for the following compounds:
sodium and oxygen ____________
calcium and fluorine______________
aluminum and sulfur______________
aluminum and chlorine_____________
IV. Other Patterns in the Periodic Table
Elements in the same vertical group or family (columns headed 1A, 2A, etc) have similar
properties, because they all have the same number of outer electrons (same as the group number)
A. Name an element that acts chemically like
Sodium _________
Both have ____outer electrons.
Iodine __________
Both have _____outer electrons.
Calcium _________
Both have _____outer electrons.
Neon ____________
Both have _______outer electrons (except He).
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B. Which element is the most abundant in the universe?_______________
C. In the atmosphere?__________________.
D. Valence of Sr ___________Valence of S _____________Valence of K_____________
E. The elements are placed in order of the TOTAL number of protons (or electrons) in the atom.
Number of protons in each of the following:
H _________
Ga __________
S _________
Kr ___________
V. Composition of the Atmosphere...Making Rust (ferric oxide)
Place some dampened steel wool into a test tube. Invert the test tube into a beaker of water.
Original height of air column is ______________cm.
Check the height of the water in a day or two. Final height of air column is ______________cm.
This tells us that the percent of oxygen in the air is__________________%.
The other gas is __________________.
The reaction is
____Fe + ____O2 reacts to produce _____Fe2O3
(fill in blanks so that same numbers of atoms appear on both sides of reaction)
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