1. Unit 2
The Periodic Table

2. History of the Table
Is an organized chart of all the elements known to science.
* most elements occur naturally [91]
* some have been created in labs [27]

3. First Periodic Table was created in the late 1800’s by a Russian chemists named Dmitri Mendeleev.

4. Mendeleev put his table in order by increasing atomic mass.

5. It is called a periodic table because of the repeating pattern of elements.
* a calendar is an example of a periodic table of days

6. Because of this pattern, Mendeleev predicted the discovery of 3 new elements.
* he predicted their approximate mass, properties, chemical activity based on their location
* he was right

7. * Today’s table is in order by increasing atomic numbers .

8. The Format of the Periodic Table
Period = a row across the table
* it shows the repeating pattern
* each period represents an energy level
* 7 periods on the table

9. 1 2 3 4 5 6 7 6 7

10. The Format of the Periodic Table
Family (Group) = a column up and down on the table
* they have similar properties
* they will react the same way
* 18 families (groups) on the table

11. 1 18 2 13 14 15 16 17 3 4 5 6 7 8 9 10 11 12

12. Some Families have names given to them.
Family 1 = Alkali Metals
Family 2 = Alkaline Earth Metals
Families 3 – 12 = Transitional Metals
(a.k.a.: transitional elements)
Family 17 = Halogens
Family 18 = Noble Gases

13. 3 Categories of Elements
Metals
Non-Metals
Metalloids

14. The Format of the Periodic Table
Metals are located on the left side.
* solids at room temperature
* mostly shiny
* good conductors
* malleable and ductile

16. The Format of the Periodic Table
What makes a METAL a METAL?
* its properties

17. The Format of the Periodic Table
Non-Metals are located on the far right side.
* mostly gases at room temperature
* some are brittle solids
* do not conduct electricity
* not malleable or ductile

19. The Format of the Periodic Table
What makes a NON-METAL a NON-METAL?
* its properties

20. Only MERCURY (metal) and BROMINE (non-metal) are liquids at room temperature.

21. The Format of the Periodic Table
Metalloids are located on the Stair-Step Line.
* have properties of metals and non-metals
* will react differently based on the situation

23. The Format of the Periodic Table
What makes a METALLOID a METALLOID?
* its properties

24. Color code
your Periodic
Table.
Page 164 of the Chemistry textbook.

26. Information found in the Periodic Table
Element name
Element symbol
Atomic number (# of protons)
also electrons
Atomic mass
State of matter
Family Number
Period (# of energy levels)

27. 15 Nitrogen 7 N 14.007 Family # Name Atomic # State of Symbol Matter
protons & electrons 7
State of
Matter
Symbol N
Atomic Mass
14.007
Period is found by following the row to the left.
# of energy levels

28. Information not found in the Periodic Table
# of Neutrons
Mass number
* the table would be TOO large
* each isotope would need its own box

29. The Periodic Table has hidden information about each element.
* you just have to know how to read what it tells you

30. An elements reactivity is based on the number of electrons in its outer energy (valence) level.
* to be stable they need 8 electrons in their O.E.L.

31. How to tell how many electrons are in the outer energy level.
Look at the Family (Group) Number / / / /
01 = 1
02 = 2
13 = 3
14 = 4
15 = 5
16 = 6
17 = 7
18 = 8
Does not hold true for families

32. Dot Diagram
Uses the element’s symbol and a dot to represent EACH electron in its outer energy level.

33. Examples of
Dot Diagrams Li Ca Aℓ Br Kr

34. Family (Group) 18 = The Noble Gases
Rarely will react with other elements.
Can combine under extreme circumstances.

35. Synthetic Elements
Created in a laboratory; are not naturally occurring.
* created by colliding elements and other particles together and forcing them to stick
* most are radioactive

36. Radioactive Element
An unstable element whose nucleus breaks down and gives off particles, radiation and energy.

37. The End