1. Cool chemistry fact of the day… Diamonds and graphite are both pure forms of carbon, BUT they have very different physical properties. DiamondGraphite -hardest material known-one of the softest materials -insulator-good conductor -highly transparent-opaque and black

3. Review : classifying the elements I zinc we need to review, just in case the things we learned about elements argon.

4. Symbols for the elements The symbols are always The capital letter is sometimes followed by one capital letter a lowercase letter

5. Symbols for the elements Most symbols are the first letter(s) of Examples: – Carbon – C – Calcium – Ca – Cobalt - Co the element’s name

6. Symbols for the elements Some symbols for common elements come from their names in this language: Examples: – ferrum – iron – Fe – aurum – gold – Au – plumbum – lead - Pb Latin

7. Are solids (except mercury) Good conductors of heat and electricity Shiny, malleable, ductile Found to the right of the “stairs” Metals

8. Some can be solid, liquid, or gas Conduct heat and electricity Not shiny or ductile Found to the right of the stairs Non-metals

9. Have properties of metals and non-metals Brittle, not ductile Never conduct electricity Are found sitting on or under the stairs Metalloids

10. Metals Metalloids Non Metals

11. Elements can be grouped into families based on their properties. Very reactive group of metals Most reactive non-metals Non-reactive non-metals Alkali metals Halogens Noble gases

12. Topic 5 – The Periodic Table Read pages 126 - 135

13. A bit of history… By 1850 scientists had identified 58 elements. Scientist tried to group the elements based on their physical and chemical properties. By the 1860’s several scientists tried to sort the elements by atomic mass

14. Remember Dalton’s atomic theory? Each element has its own type of… All atoms of the same element are… atom identical

15. Atomic mass According to Dalton’s atomic theory, each element has its own kind of atom with a specific atomic mass that is different from the atomic mass of any other elements Atomic mass is the average mass of an atom of an element

16. Mendeleev (1834-1907) Created a system of organizing all of the known elements Used rows ( )and columns ( ) Organized them based on atomic mass Put elements with similar properties into groups or families Noticed that some elements were missing on his table

18. Your turn to be Mendeleev! Your group will receive information about 20 elements that have been discovered in an alien universe (They are not the same as our elements!) Arrange them in order of increasing atomic mass Look for properties that are similar among the elements and place them above and below each other in a family. Figure out a way to make families and keep them elements in order by mass! Like Mendeleev, you will need to leave spaces.

19. What did you find out? 1)How did you make families? 2)Did you have to leave any spaces? Why? 3)Which cards probably represent metallic elements? How about non-metallic elements? Explain your reasoning. 4)At room temperature, which elements are solids? Which are liquids? Which are gases? How do you know?

20. Every element has its own number An element’s position in the periodic table is determined by its atomic number The numbering system begins with hydrogen (H), atomic number 1, and moves from left to right. The numbers skip any blank spaces, so Helium (He) has atomic number 2

21. Which has the larger atomic number? carbon (C) or silicon (Si)?silicon (Si)

22. Which has the larger atomic number? silicon (Si) or phosphorus (P)? Phosphorus (P)

23. Which has the larger atomic number? beryllium (Be) or sodium (Na)? Sodium (Na)

24. Every element is part of a group Each vertical column in the periodic table is called a group Chemical families are located in the same group There are 18 groups

25. Every element is part of a period The horizontal rows in the periodic table are called periods There are 7 periods You will learn more about what elements in the same period have in common tomorrow!

26. What element is it?

29. Reading information on the periodic table 12.01 C 6 Carbon symbol atomic mass atomic number

30. Atomic number Is the number of protons in one atom The number of electrons is equal to the number of protons 12.01 C 6 Carbon atomic number

31. Atomic mass Is the average mass of an atom of an element Is the number of protons + neutrons in one atom 12.01 C 6 Carbon atomic mass

32. Example - Carbon Protons = Electrons = Neutrons = 12.01 C 6 Carbon 6 6 mass - protons = 12 – 6 = 6

33. You try! For each of the elements listed, find: – Name of the element – Atomic number – Atomic mass number (can be rounded) – # protons – # electrons – # neutrons

34. Check your understanding… Page 135 # 1, 2, 3 (choose any 5 elements of the first 18), 4, 5