# The Periodic Law

THE PERIODIC LAW

OBJECTIVES:

In this exercise, you will

·  arrange the representative elements (groups 1, 2, 13-18) according to a list of clues and your knowledge of periodic properties,

·  predict the missing properties of each element based on location in the table, and

·  explain the trends of properties in families and periods.

PROCEDURE:

1.  Locate Tables 1 and 2, attached. Each block on the table represents a different element from the main group (representative) elements.

2.  Use the following clues and arrange the elements in their proper order (in pencil) on Table 2 in periods 1 to 4 ONLY. When you have placed these 26 elements in their correct position, cut them out of Table 1 and glue them in place on Table 2. The following sets of elements belong together in groups: ZRD, PSIF, JXBE, LHT, QKA, WOV, GUN, and YMC.

J has an atomic number three times that of T. U has a total of six electrons.
Z has the smallest atomic mass in its group. I2A is the simple formula of an oxide.
O has an atomic number larger than V. P is less dense than S.
D has the largest atomic mass of its group. S is an alkali metal.
C has five electrons in its outer energy level. E is a noble gas.
X has an atomic number one higher than F. W is a liquid.
The atomic mass of T is more than that of H. B has ten protons.
Atoms of I are larger than those of S. F is a gas.
M has an atomic number one less than that of A. O is a halogen.
The atomic radius of K is the largest of the group. V is a metalloid.
L is an alkaline earth element with atomic mass of 40. O has an atomic mass 2 times that of A.
Electrons of atom N are distributed over 3 energy levels.

3.  Cut out the remaining 16 blocks. Use the information provided in each block and your knowledge of periodic properties to arrange these elements in their proper position on Table 2. Glue the blocks in place.

4.  Some information is missing from each block. Predict the values for the missing items from the location of the element on the periodic table. Place your predictions on the table. (You may use the periodic table to determine the symbol for each element.)

CONCLUSIONS:

1.  Examine your completed table. What general observations can be made of trends within periods for the following properties?
a. ionization energy(potential) b. covalent radius c. electronegativity

2.  What general observations can be made of trends within groups for the following properties?
a. ionization energy(potential) b. covalent radius c. electronegativity

3.  List two physical properties which distinguish metals from nonmetals.

4.  Closely look at the trends for physical properties of your elements. Where do the trends appear to “break down” in the groups? In the periods? Suggest a reason for this.

5.  Using electronic configurations, explain why groups 3-12 are dropped from this exercise.

6.  Again using electron configurations, suggest a reason why some elements have multiple charges.

Revised 11/09