Chemistry/Mendeleev

Science 10 Mendeleev’s Periodic Table

In this activity you will be given a chart containing the properties of eighteen “known” elements or compounds and a set of ten “unknown” elements or elements.

PROCEDURE 1. Cut out the 10 “unknown” cards below. You should notice that there are 12 possible locations to place the 10 cards — when you are finished, there will be two numbered locations which are not covered by an “unknown” card (this helps to keep you on your toes). 2. Examine the set of “known” elements or compounds on the large sheet, become familiar with the properties listed and make predictions of the properties for the blank positions labeled 1 to 12. 3. Each VERTICAL COLUMN in the periodic table is called a FAMILY and each HORIZONTAL ROW is called a PERIOD. Examine the set of “unknowns” and decide where each of these “unknowns” fits in the periodic table, based on the way the properties of each “unknown” fit into each vertical family. Note: only families 1, 2, 11, 14, 17 and 18 are included in this activity. 4. By referring to a periodic table, identify each of the “unknowns” by its appropriate chemical symbol. When all of the “unknowns” have been identified, glue or tape them into place.

QUESTIONS

1. How were elements in Medeleev’s periodic table arranged?

2. What is Medeleev’s periodic law?

3. Why was Mendeleev able to predict the properties of elements which had not yet been discovered?

4. Do all the properties follow a smooth trend when comparing the elements or compounds in a family? Support your answer using data from your finished chart.

5. You have been called in as a highly paid consultant to the Atomic Energy Commission to predict the properties of Element 114. Although this element has not been discovered, nuclear physicists are sure that they can make it some day soon. Your task is to predict as many as you can of the properties of Element 114, which will lie directly underneath the element lead (Pb) on the periodic table. They are paying you for every property you predict, so if not sure, make a good guess.

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