Understanding the Periodic Table: History, Structure, and Chemical Properties

1. TOIPC: Periodic Table Organization Do Now: From your activity yesterday, and p.5 answer page 6 in your packet

2. Periodic Law • There is a periodic repetition of chemical and physical properties of elements when arranged by increasing atomic number

3. What is the periodic table? • compact way of organizing elements • contains a lot of information • allows us to make predictions about behaviour and properties of elements • Elements

4. The periodic table hasn’t always look like this

5. History of the Periodic Table • End of the 1700’s – less than 30 elements known • Many elements discovered during 1800’s • Many experiments done to determine atomic masses

7. John Newlands • 1864: if elements arranged by atomic mass - properties repeat every 8th element • Law of Octaves • did not work for all known elements • Key idea was correct: Properties of elements do repeat in periodic way

8. Mendeleev & Meyer Mendeleev produced 1st accepted PT: 1869 • Elements ordered by ↑ atomic mass into columns with similar properties • Predicted existence & properties of undiscovered elements • Not totally correct • more accurate atomic mass calculations showed some elements weren’t in right place

10. Remember 1860’s: • No subatomic particles yet discovered • Dalton’s billiard ball model of the atom

11. 1913 – Henry Moseley • by 1913, protons & electrons discovered • Neutrons were predicted • Moseley determined atoms of each element contain unique # protons (= atomic number) • rearranged Mendeleev’s PT by atomic number instead of mass • problems with elements in wrong place disappeared

13. Periodic Table is arranged according atomic number and organized into groups and periods

14. COLUMNS Groups/Family numbering (1  18) left to right TELL US NUMBER OF VALENCE ELECTRONS (KIND OF)

15. Valence Electrons – electrons in the outer shell • Chemical behaviour determined by # valence electrons • Elements with same # valence electrons will have similar chemical properties • Elements in same column have similar chemical properties

16. Period Element Configuration 1 H 1 2 Li 2-1 3 Na 2-8-1 4 K 2-8-8-1 5 Rb 2-8-18-8-1 6 Cs 2-8-18-18-8-1 7 Fr 2-8-18-32-18-8-1 Going Down Column 1:

17. Group Number of Valence Electrons 1 or IA 1 2 or IIA 2 13 or IIIA 3 14 or IVA 4 Valence Electrons

18. COLUMNS CO L U MN • Aka groupsor families • #1 thru 18, Arabic numerals • (old way, Roman Numerals and letters) • - tell us number of valance electrons • (KIND OF) = works for 1,2, 13,14,15,16,17,18 Turn to packet page one, lets label the columns and valence electrons

19. Names of Families(AKA group A elements) • Group 1 = Alkali Metals • Group 2 = Alkaline Earth Metals • Groups 3-12: Transition metals • Group 17 = Halogens • Group 18 = Noble Gases

20. Transition Metals (in yellow) • Groups 3 through 12

21. form brightly colored salts

22. Glenn Seaborg: 1950’sf-Block Metals • Lanthanide (rare Earth metals) – can be found naturally on Earth, only 1 is radioactive • Actinide– all are radioactive, some are made in the lab. INCLUDES Uranium Turn to packet page one, lets label the the f-block metals

25. ROWS Period numbering (1  7) top to bottom TELL US NUMBER OF SHELLS (energy levels)

26. Energy Levels = Row Number • Elements in same row have same # of principal energy levels

27. ROWS • Rows are called series or periods • #1 thru 7 - TELL US HOW MANY ENERGY LEVELS ROW Turn to packet page one, lets label the periods