Introduction to Periodic Table

1. Introduction to Periodic Table

2. Dmitri Mendeleev • 1869 • Organized the 63 known elements • Put properties on cards and looked for trends • Ordered elements by atomic weight, organized so there were repeating patterns both across & down

3. Mendeleev’s Periodic Table

4. While coming up with his order, Mendeleev…. • Found errors in atomic weights of 17 known elements • Left places for undiscovered elements & predicted their properties • 3 of those were discovered in his lifetime: gallium, scandium, germanium

5. Ekasilicon & Germanium

6. Henry Mosley • British chemist -1915 • Found inconsistencies with Meneleev’s Periodic Table • Arranged elements by atomic number • Inconsistencies disappeared • Arranged the periodic table for today

7. The Periodic Table

8. Design of the Periodic Table • Classification of Element • By looking at where a element is on the periodic table, you can tell about it’s chemical and physical properties • Columns (18) • Up and down • Called Families/Groups • Elements in Families have similar properties • Rows (7) • Side to Side • Called Periods • Elements in periods DO NOT have similar properties

10. 1A 8A 2A 3A 4A 5A 6A 7A • The first two and last six columns are numbered 1A-8A, relates to the # of electrons in their OUTER shell.

12. Properties of the metals • Left side of PT • Physical Properties • Luster- Shininess • Ductile – Draw into wire • Malleable- hammered into sheets • Good Conductor of heat and electricty • Chemical Properties • Corrosive- wearing down due to chemical reaction • Easily lose electrons

13. Alkali Metals • Group 1/ 1st Column • Very reactive • Form +1 ions • Soft metals – cut with butter knife • Low density • Never found unreacted in nature • Cations • Examples: H, Li, Na

14. Alkali and a Halogen Missing Electron Extra Electron

15. Alkaline Earth Metals • Group 2/Second Column • Reactive (not explosive) • Rarely found unreacted in nature • Form 2+ ions • Cations • Examples: Be, Mg, Ca, etc

16. Transition Metals • Groups 3B-12B on the Periodic Table • Middle section of PT • Much less reactive than Alkali or Alkaline Earth Metals • often unreactive • Only 1 that is a liquid at room temp • Mercury – Hg • Examples: Cr, Co, Ni, Fe, Cu, Ag, Au

17. Properties of rare Earth metals • Lanthanides • Rare Elements • Actinides • Radioactive • Not often found in compounds • Some are not found in nature at all • Properties: • Silver, silvery-white, or gray metals. • The metals have a high luster, but tarnish readily in air. • High electrical conductivity. Lanthanides - part of period 6 Actinides - part of period 7

18. Properties of Metalloids • “Stairstep” between metals and nonmetals • Properties • Can have both metals and non metals traits • Sometimes called semiconductors • Technology • Can be shiny or dull, malleable or not… • Example: Fe, Cu

19. Properties of non-metals • Right Side of PT • Physical Properties • Dull • Brittle • Good insulator • Poor conductors • Solid, Liquid, & Gas • Chemical Properties • Tend to gain electrons

20. Halogens • Group 17 • Very reactive • “Salt-formers” • Form -1 ions • Anions Examples: Chlorine Bromine Iodine

21. Properties of Noble Gases • Group 18 • Unreactive, inert, “noble” • Low Boiling Point • Gases at room temp • Have a 0 charge, no ions • Examples: He, Ne, Ar, Kr, etc

23. Diatomic Gases • Group of gases • Paired when found in nature • H O N Cl Br I F H2 O2 N2 Cl2 Br2 I2 F2