Subject Area Lessons

## #3657. History of the Periodic Table

Science, level: Senior
Posted Thu Feb 9 11:22:45 PST 2006 by Melissa Magill (magillmr@pickens.k12.sc.us).
Easley High School, Easley, SC, USA
Materials Required: a set of at least 3 shapes each in at least 3 colors for each group
Activity Time: 30 - 45 minutes
Concepts Taught: periodic table, organizational systems

DISSCUSSION
Tell me some different types of organizational systems.
How often do you use an organizational system?
Why do we use them?
Name as many as you can that relate to science particularly.
ACTIVITY
-Each group needs to get a baggie of shapes. I want you, as a group, to come up with an organizational system that makes some type of sense, which you can explain, and uses all of your shapes.
-(Whole class) Discuss each group's method.
TRANSITION
-Why do we organize things into systems?
-Discuss life/chemistry without the periodic table.
DISCUSSION OF NEW MATERIAL
-John Newlands, in the 1860's, organized 16 of 17 known elements into 2 rows by increasing atomic mass. Each element had similar properties to the element above or below it.
-In 1869 Dmitri Mendeleev expanded this idea. He took 63 known elements and wrote the symbol and chemical and physical properties for each element on a card. He organized them in a sensible way -- increasing atomic mass, again putting similar elements in columns.
Problems:
2. some gaps, but he predicted properties of undiscovered elements fairly accurately.
WHY WAS MENDELEEV'S WORK A BIG DEAL?
-40 yrs later, Henry Moseley found a physical basis for the periodic nature of the elements. When using X-ray spectra, he realized that wavelength decreased as atomic mass increased -- usually. He studied and found out that it's not by atomic mass but atomic number.
TELL ME some noteworthy things Mendeleev did in the development of the modern periodic table.
-And Moseley.
STUDY TIP: Both names start with M, but e comes before o alphabetically and Mendeleev came before Moseley.
INDEPENDENT ASSESSMENT
- Make a Venn diagram comparing Mendeleev's and Moseley's contributions including
-type of row arrangement
-column arrangement
-problems (if any)
-benefits / achievements --CULTURAL EXPANSION
OK, did anyone notice what Mendeleev's first name was?
-Does that give you clue as to where he was from?
PASS AROUND A RUSSIAN PERIODIC TABLE