Create a Table

QuickTime™ and a QuickDraw decompressor are needed to see this picture.

ChemCatalyst

• In 1889 a Russian chemistry teacher created an organized table of the elements. At the time only 63 different elements were known. Below is a reproduction of that table.

– What do you think the numbers represent?

(cont.)

The Big Question

– How did Mendeleyev organize the elements?

You will be able to:

– Explain how the periodic table of elements is organized.

– Dimitri Mendeleyev is credited with organizing the elements into the first periodic table.

– The main properties that Mendeleyev used to sort the elements were reactivity with one another and a number describing the atomic weight of each element.

Notes

Activity

• Purpose: The goal of this lesson is to acquaint you with Mendeleyev’s organization of the elements by allowing you to create your own table from the patterns you see in the elements.

Making Sense

• Below are five possible cards for the

element germanium. Where does

germanium belong in the table? Which

card seems most accurate to you? What

is your reasoning?

(cont.)

Germanium

Ge62.7

Germanium

Ge62.7

Germanium

Ge66.0

Germanium

Ge72.6

A B C

D E

Germanium

Ge72.6

(cont.)

– What would you add to the three empty

corners to complete the card?

Germanium

Ge

(cont.)

(cont.)

Completed Table(cont.)

Check-In– Which of the following elements would

you find in the same group on the periodic table? Explain your thinking.

CadmiumCd

Moderately soft, silvery solid,

metal

React very slowly with water

Found inCdCl2 (s)

ZincZn

Moderately hard, silvery solid,

metal

Reacts very slowly with water

Found in ZnCl2 (s)

IodineI

Purple solid, nonmetal

Reacts slowly with metals

Found inICl (s)

MercuryHg

Silvery liquid, metal

Does not react with water

Found inHgCl2 (s)

Wrap-Up

– Mendeleyev organized the periodic table based on the properties of the elements.

– Mendeleyev’s arrangement of the elements helped to predict the existence of undiscovered elements.