1. Create A Table

2. 1) How do you think the elements are organized?
Show students this page and explain: In 1889 a Russian Chemistry teacher named Dmitri Mendeleyev created an organized table of the elements. At the time only 63 different elements were known. This is a reproduction of this table.
Take 5 minutes and answer the questions on a piece of paper. After 5 minutes randomly call on three students to answer each question. Don’t correct or add to their answers, just see what they know or observe.
Then, move on to next slide.
Observe the table above and answer the following questions on a piece of paper:
1) How do you think the elements are organized?
2) What do you think the numbers represent?
3) What do you notice about the numbers as you go across the table? Down?
4) What do the blank spaces represent?

3. Dmitri Mendeleev – Credited with organizing the elements into the first periodic table in 1869.
One group of elements Mendeleev placed together: Be Mg Ca Sr
How Mendeleev sorted his elements:
1) Reactivity
(does an element react with other elements and how violently does it react?
2) Atomic weight
In Mendeleev’s day chemists calculated the atomic weight by looking at proportions in which elements combined with each other to form new substances.

4. Create A Table Activity (15 min.)
Use the grouping below as your starting point:
Call me over when done to check! Be Mg Ca Sr
Hand out worksheets. Have students get into groups and hand out sets of cards.
You could draw the grouping of Be-Mg-Ca-Sr on the board so that you can shut off the projector for 15 min.

5. Post-Activity Discussion: Sorting Activity
Answer the following questions on a piece of paper (one per group). Put all group members names on the paper.
1) How did you sort your cards?
2) What characteristics did you use for sorting?
3) Did you have to abandon any characteristics and pick different ones? Explain.
4) Did you discover any new characteristics of patterns during the activity? Explain.
5) Look at each column, is there a pattern in properties, reactivity, and atomic size? Explain.
Give students a couple minutes to answer these questions on a piece of paper then call on different groups (or all if there is time) to answer the questions.

6. Making Sense
Which card did you choose for Ge? (A, B, C, D, or E)

7. Post-Activity Discussion: Missing Element
Answer the following questions on the same group paper:
Do you predict Ge will be a solid, liquid, or gas (at room temp.)?
Do you predict Ge will be shiny? Explain.
How do you expect Ge will react with air? Explain.
Do you expect Ge to form GeH2, GeH3, or GeH4?
How do you think Mendeleyev was able to predict new elements before they were discovered?
Have students answer these questions on the same sheet of group paper before discussing it with the class.
If they run out of time they should answer the questions and just hand the paper in.
FYI: Card D is the most accurate one. The number on this card is somewhere between the numbers of Gallium and Arsenic, which are on either side of the table on Mendeleev’s table. The size of the circle shown best fits between Gallium and Arsenic horizontally and Silicon and Tin vertically. Also, the element should have four spokes. Regarding the three missing corners of the card, students should say something close to the following: 1) Moderately soft, silvery solid, metalloid, 2) forms GeH4 gas and 3) corrodes very slowly in the air.