1. The Periodic Table

2. REVIEW All atoms of a specific element are alike
All atoms of different elements are different
90 naturally occurring
Arranged on Periodic Table to show trends

3. A Brief History of the Periodic Table
Mendeleev – Moseley - Seaborg

4. Mendeleev (1869) Thought pattern must exist between all elements
Organized table by...
ATOMIC MASS
Elements in columns show similar properties…
Both physical and chemical!
Predicted properties of “missing” elements

5. Mendeleev’s TABLE
His notes

6. What he thought!
“I began to look about and write down the elements with their atomic weights and typical properties, analogous elements and like atomic weights on separate cards, and this soon convinced me that the properties of elements are in periodic dependence upon their atomic weights.”
Mendeleev, Principles of Chemistry, 1905, Vol. II as quoted at <

7. Definition What does PERIODIC mean?
A repeating pattern
Mendeleev left some spaces in his table because not all elements lined up according to atomic mass. He used info he knew about surrounding elements to PREDICT properties and masses of unknown elements.
How about that!

8. Mendeleev’s Predictions vs. Actual Properties of Element # 32
“Ekasilicon”
Germanium
Date
1871 (predicted)
1886 (discovered)
Atomic Mass 72
72.6
Density
5.5 g/cm3
5.47 g/cm3
Bonding power 4
Color
Dark gray
Grayish-white

9. Moseley (c. 1914) rearranged table by ...
ATOMIC NUMBER
determined atomic number of elements by using x-rays to determine number of protons in element

10. Moseley’s work

11. Seaborg (1944) rearranged Periodic Table with...
Lanthanide and Actinide Series pulled out/separated from main Periodic Table
discovered 10 new elements & countless isotopes

12. 3D Alexander’s Arrangement of Elements

13. definition Periodic Law
The physical and chemical properties of the elements are periodic functions of their atomic number

14. definition
Octet Rule
The tendency of atoms to gain or lose electrons so they acquire eight electrons in their outer energy level

15. Columns of Table = groups or families
Numbered 1 – 18
Group numbers tell us the number of electrons in that element’s outer energy level - the number in red
Elements within the same family have similar but not identical properties 16 18 1 2 15 17 14 13

16. definition Valence electrons
electrons found in the outermost energy level
use the group number (the number in red) to determine number of valence electrons

17. NAMES to Know

18. NAMES to Know
Group 1
Alkali Metals

19. NAMES to Know
Group 2
Alkaline Earth Metals

20. NAMES to Know
Groups 3-12
Transition Metals

21. NAMES to Know Inner Transition Metals: Lanthanide Series
Actinide Series

22. NAMES to Know
Group 16
Chalocgens

23. NAMES to Know
Group 17
Halogens

24. NAMES to Know
Group 18
Noble Gases

25. Rows of Table = periods 7 periods Period = # of energy shells in atom
Properties are not alike within a period:
across each period (row), the chemical & physical properties of elements change
these properties are repeated in the next period (the row below)

26. Periods 1 to 7 1 2 3 4 5 6 7

27. Regions of the Periodic Table
Metals - to the left of the stair-step line
Non-Metals - to the right of the stair-step line
Metalloids - along the stair-step line

28. Regions of the table
One more!
NONMETALS
METALLOIDS
METALS

29. Metals Found to LEFT of zigzag line on table
Good conductors of heat & electricity
Malleable
Ductile
High melting points
Shiny
Tend to lose electrons
 forming cations

30. Nonmetals Found to RIGHT of zigzag line on table
Plus Hydrogen (atomic number = 1)
Poor conductors of heat & electricity
Brittle when solid
Dull
Low melting points
Tend to gain electrons
 forming anions

31. Metalloids aka Semi Metals
Found along both sides of zigzag line
Properties of both metals & nonmetals
Okay conductors of heat & electricity
Shiny or dull