Introduction to Periodic Table

Sixty-three elements had been discovered by 1869. As more elements were discovered, scientists recognized similarities and patterns in the properties of elements, and some scientists proposed classification schemes. 

In 1817, Johann Dobereiner realized that calcium, strontium, and barium have similar properties and that the atomic weight of strontium is about halfway between those of the other two elements. After discovering the triad of chlorine, bromine and iodine and the triad of lithium, sodium, and potassium Dobereiner proposed his law of triads. In nature, there are triads of elements in which the middle element has an atomic weight that is the average of the atomic weights of the other two elements in the triad. 

Between 1829 and 1858, several scientists worked on the idea of triads. They discovered that the chemical relationship extended beyond groups of three. They begin to group elements into groups and families. 

The modern periodic table is credited to Russian scientist, Dmitri Mendeleev. 

This quest will lead you through an explanation of the periodic table we know and use today. 

The periodic table gives you the name, symbol, atomic number and atomic mass of each element. 

Your task is to learn what each of these is and what information it tells you about the element. You will also learn how the elements are arranged on the periodic table. You will also need to record where you found each answer. 

You will be given a worksheet containing the following questions. 

You must search the internet to complete these questions. You must list the URL or website where you found each answer. 

1. How was the first periodic table arranged?What was the problem with the first arrangement?

2. What do the elements in the same group have in common? Which direction do groups go on the periodic table?

3. What do the elements in the same period have in common? Which direction do periods go on the periodic table?

4. How many groups and how many periods make up the Periodic Table?

5. What is atomic mass?

6. What is atomic number?

7. How can you find the number of neutrons in an atom?

You will be evaluated on your efficiency and the accuracy of your findings. If you do not cite your sources you will lose points. If you do not answer the questions you will lose points. 

Awesome job!

Now you have learned the information that you need to use the periodic table as a scientist. 

Holt Science and Technology North Carolina Grade 8

Students: 

This webquest was designed for 8th grade Science. 

Standards: 

The standards are based on North Carolina Science Essential Standards and the Common Core State Standards.

8.P.1.2 Explain how the physical properties of elements and their reactivity have been used to produce the current modle of the Periodic Table of elements. 

CCSS.ELA-LITERACY.RST.6-8.1 Cite specific textual evidence to support analysis of science and technical texts.

CCSS.ELA-LITERACY.RST.6-8.4 Determine the meaning of symbols, key terms, and other domain-specific words and phrases as they are used in a specific scientific or technical context relevant to grades 6-8 texts and topics.