Lab Activity 10: The Periodic Table

Purpose & Some Background:

In 1869, Dmitri Mendeleev wanted to develop and organize all the elements that had been discovered. He wanted to do this in a meaningful and orderly way; therefore, he organized them by increasing mass. He placed elements that had similar patterns of chemical behavior/properties into the same groups. Thus we have the 18 groups (18 columns) in the periodic table. He published this table in 1871, although it was incomplete (not all of the elements were discovered yet), he was able to predict the properties of these elements. These predictions were possible because he organized the periodic table into groups of similar properties.

Trends in the chemical and physical properties of elements may be seen as a periodic function of electron configuration (the properties are related to the number of electrons in a particular atom.) You will examine several properties (atomic number, ionization energy, electronegativity, and atomic radius) of elements and observe how these properties may be interpreted.

Teacher’s Note:

By the end of this lab, I want you to:

1. Understand the relationship between electron configuration and the location of an element within the periodic table.

2. Examine and graph periodic trends in ionization energy, electronegativity, and atomic radius.

Materials:

-Reference Tables -Pencil -Ruler

-Graph Paper -Calculator

Procedures:

1. You must incorporate the first 20 elements in this lab exercise. Create a data table containing the required information (Atomic number, ionization energy, electronegativity, and atomic radius) for the first 20 elements.

2. Create graphs of each property v. atomic number (eg. Ionization energy v. atomic number, electronegativity v. atomic number, etc..)

3. Observe these graphs and explain trends or patterns that you see.

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