1. Organizing the Elements

2. Dmitri Mendeleev Russian 1869 Looking for patterns in element behaviors

3. Patterns F and Cl both irritating gasses Cu and Ag both tarnish when exposed to air Li, Na, K react violently with water

4. Atomic Mass Patterns appeared when arranged in order of increasing Atomic Mass Atomic Mass: Avg. mass of all the isotopes of that element

5. Predicting When arranged not all elements agreed with the patterns Mendeleev predicted that more elements existed (SC, Ga, Ge) and their properties Within 16 years they were found

6. Today’s Table Properties of elements repeat in periods ◦ Periods are the rows 1913 Henry Moseley measures charges

7. Moseley Rearranges by atomic number ◦ Elements can now be identified by their protons as opposed to their Atomic Mass

9. Symbol Most are English abbreviations Find some elements and their symbols that are not Look on pg 85

10. Organization Properties of elements can be predicted from its location on the table Periods Groups

11. Periods Rows Moving across the properties of elements change to pattern Left = highly reactive metals Right = unreactive gasses 7 periods

12. Groups Columns Also called families Elements in each group have similar properties 18 groups

13. Al Look at the different items List as many properties as you can about each Why is Al used to make each item? What other items are made from Al? What other elements have similar properties?

14. Assignment Pg 87 1-3 all parts Exit Slip: write 3 things you learned about the Periodic Table of Elements