The Periodic Table

1. The Periodic Table

2. most of the pure elements are solid at room temperature, only 11 naturally occurring elements are a gas, and only 2 elements are liquid at room temperature

4. Dmitri Mendeleev (1829-1869) • organized a “Periodic Table” (only knew about 63 elements at the time) based on increasing atomic mass • the properties of elements had something to do with their mass • even left empty spaces to be filled in later

7. Main “categories” of elements

8. Metals • shiny • ductile • malleable • good conductors of heat and electricity • have high melting points • will corrode (rust) in water or air • generally give away electrons

10. Nonmetals or gases • located to the right of the zig-zag line in the periodic table • often are different from one another • dull • do not conduct heat and electricity • are not malleable nor ductile • have a tendency to gain electrons

11. Metalloids • elements on the “zig-zag line” • have some characteristics of both metals and nonmetals

12. Groups are the vertical columns. • elements have similar, but not identical, properties • most important property is that they have the same # of valence electrons

13. Alkali Metals • most reactive of the metals because they all lose one valence electron VERY easily • soft metals

14. http://www.microchem.de/elec000a-k.JPG

15. Alkaline Earth Metals • harder and denser than alkali metals • not as reactive as the alkali metals

17. Transition Metals (Elements) • display typical metallic characteristics • can share or give away valence electrons depending what they chemically combine with

19. Halogens • form diatomic molecules • (F2 Br2 I2 Cl2 ) • all gain one valence electron VERY easily

20. Noble Gases • mostly unreactive because their valence level is full (2,8,8….) • colorless, odorless gases

22. Mixed Groups • not as similar to each other as other groups • usually named after the first element in the group (B C N O)

23. Rare Earth Elements • many are synthetically produced (not actually rare) • have been separated from the others to make the table not as wide • used in the nuclear industries, metallurgy, ceramics, electrical components…

24. Periods are the horizontal rows • do NOT have similar properties • however, there is a pattern to their properties as you move across the table