Name:_____________________
CREATE A TABLE
Introduction: In 1889, Dimitri Mendeleev, a Russian chemistry teacher, came up with an
ingenious organization of the 63 known elements. He organized the elements according
to their properties. This organization evolved into our contemporary periodic table.
Mendeleev was even able to predict the existence of as-yet undiscovered elements based
on gaps located in this table. It is said that Mendeleev went to sleep one night and dreamt
of a table where the elements were organized by similar properties. In his mind they
simply fell into their appropriate places. Upon awakening, he applied his dream to the
task at hand, finding patterns in the repetitive properties of the elements.
Instructions Part I:
1. You have a set of 33 element data cards. Each card lists some of the properties of
the elements. The circles represent the relative size of each element.
2. Color all the metal circles blue. Color all the gas circles yellow. Color all the
liquid circles red. Color all the non-metal circles green. Color all the semi-metals
orange.
3. Cut out all of the cards.
4. Find the cards with an atomic mass of 9.01, 24.31, 40.08, and 87.62. Place them
in a column in order of increasing atomic mass (with the least mass on top and the
most mass on the bottom).
5. Decide how you can use the remainder of the cards to organize the elements into a
table similar to Mendeleev’s.
6. Arrange the cards and glue them down in that order on a piece of paper.
7. Answer the following questions.
Questions:
1. What characteristics did you use for sorting the cards?
2. Where did you put the atomic mass 1.01 card and the 4.00 card? Why?
3. Did you notice any cards that didn’t quite fit, or that seemed out of order? If so,
which ones and why?
Instructions Part II:
1. Use your periodic table in your planner or the back of your textbook to find the
atomic number of each of your 33 elements. Write the number next to the circle
of each element.
2. Make a graph of atomic number vs bonding with chloride.
a. label the X axis with atomic numbers.
b. label they Y axis for the number of chlorine atoms with 0 for none bonds,
1 for one chlorine, 2 for two chlorines, etc…
c. plot the data from the element cards.
Questions:
1. Does the graph reveal a repeating or cyclic pattern?
2. Is the graph consistent with your earlier grouping of the elements (does it show
the same pattern, is it arranged the same way)? Why or why not?
Instructions Part III:
Some properties of an element can be estimated by averaging the properties of the
elements located just above and just below the element in question. This is how
Mendeleev predicted the properties of elements unknown in his time. He was so certain
about his conclusions that he left gaps in his periodic table for missing elements, with
predictions of their properties. When these elements were eventually discovered, they fit
in exactly as expected. Mendeleev’s fame rests largely on the correctness of these
predictions.
For example, germanium (Ge) was an element undiscovered when Mendeleev
proposed his periodic table. However, in 1871 he predicted the existence of germanium,
a blank spot of the periodic table above tin and below silicon (he named it ekasilicon).
Given the information that the boiling points for silicon (Si) and tin (Sn) were 3267 C and
2603 C respectively, we can estimate the boiling point of germainium.
(3267 C) + (2603 C) = 2935 C
2
Use the above information to answer the following questions:
1. The element krypton was not known when Mendeleev developed his periodic
table. Given that under similar pressure the boiling point for argon (Ar) is -186 C,
and for xenon (Xe) is -112 C, estimate the boiling point of krypton.
2. a. Estimate the melting point of rubidium (Rb). The melting point of potassium
(K) and cesium (Cs) are 64 C and 29 C, respectively.
3. Would you expect the melting point of sodium (Na) to be higher or lower than
that of rubidium? Why?
4. Mendeleev knew that silicon tetrachloride (SiCl4) existed. Using his periodic
table, he correctly predicted the existence of “ekasilicon”, an element one place
below silicon in the periodic table. Use your periodic table to write the formula
for the compound formed by Mendeleev’s “ekasilicon” and chlorine.