History of the Periodic Table Webquest

Use the following site to answer questions:



1. Law of Triads:

a. What are the two sets of triads Dobereiner observed?

b. What is the Law of Triads:

2. Law of Octaves:

a. What did De Chancourtois first recognize with his chart?

b. John Newlands developed a chart (with rows and columns).

How many elements were in each column before he started the next column:


3. Two Fathers of the Periodic Table?

a. Who were the two scientists that could be argued the Father of the Periodic Table?

b. Meyer’s work was based on valence charges and atomic weights.

He created a chart - make a sketch of the graph from the following site: http://web.lemoyne.edu/~giunta/meyer.html to sketch the graph

If this link is not working, try one of these...

or http://dl.clackamas.cc.or.us/ch104-07/lothar_meyer.htm

How does this violate Newlands’ Law of Octaves?


4. “The” Father of the Periodic Table:

a. Mendeleev first organized the elements by :

b. Then with the metallic elements, he began to order them by

c. Going down a group (or family), how did Mendeleev order the elements?

d. Mendeleev was bold to change what accepted property of beryllium?

e. To Mendeleev, which was more important, weight or correlating properties?

f. What did Mendeleev do with his gaps in his table?

g. What was the flaw in reasoning that caused Mendeleev to mix up the placement of Ar and K, Co and Ni, and Te and Ni?


5. After Mendeleev:

a. What group of elements had been discovered after Mendeleev’s initial work? Why do you think this is so?

b. What was this group labeled “zero”? Was this a good choice?

c. After Rutherford, van den Broek, and Mosely, the property that varies periodically with properties of the elements is:

d. Bohr’s studies helped to organize the electrons within an atom, leading to the reasoning behind the periodic law. As you go down a group, what is similar about their electron configuration?

e. Seaborg is the last scientist to contribute to the organization of the modern periodic table. What did he do to change the shape of the table?