1. History of the Periodic Table

2. The Beginning…
In Chemistry, we have organized the elements that compose our world into the Periodic Table of Elements
The word periodic means “repeated in a pattern”

3. Dmitri Mendeleev Dmitri Mendeleev (1869, Russian)
Started with 63 known elements
Organized elements based on similar properties.
Organized elements by increasing atomic mass.

4. Dmitri Mendeleev
Predicted the properties and atomic masses of unknown elements where there were empty spaces.
His pattern formed columns where all of the elements in the columns showed similar physical and chemical properties

5. Henry Mosely Henry Mosely (1913, British)
Organized elements by increasing atomic number.
Fixed problems in Mendeleev’s arrangement.

6. Periodic Law
States that the physical and chemical properties of the elements are periodic functions of their atomic numbers

7. The Periodic Table
Organization

8. Terms
Groups or Families – vertical columns
Period – horizontal rows

9. Periodic Trends Group # = # of valence e- (except He)
Families have similar properties.
Period # = # of energy levels 1A 2A
3A 4A 5A 6A 7A 8A

10. The Period Table
Naming

11. Columns & Rows Group 1 - Alkali Metals Group 2 - Alkaline Earth Metals
Groups 3-12 – Transition Metals
Group 13 - Boron Family
Group 14 - Carbon Family
Group 15 - Nitrogen Family
Group 16 - Oxygen Family
Group 17 - Halogens
Group 18 - Noble Gases

12. Rare Earth Family Rare earth metals belong between families 3 and 4
They are typically below the rest of the table to save space

13. Table Sections Representative Elements Transition Metals
Rare Earth Elements

14. Table Sections Overall Configuration Lanthanides - part of period 6
Actinides - part of period 7

15. The Periodic Table
Periodic Trends

16. Periodic Trends
Valence Electrons
Increases as you move RIGHT

17. The periodic number tells you how many energy levels there are in an atom
They do not have the same properties

18. Periodic Trends
Energy Levels
Increases as you move DOWN.

19. Periodic Trends
Atomic Radius
Increases to the LEFT and DOWN.

20. Be or Ba Ca or Br Ba Ca Periodic Trends
Which atom has the larger radius?
Be or Ba
Ca or Br Ba Ca

21. Mass Number vs Atomic Mass
Recall…
The mass number is the sum of the protons and neutrons
The Atomic mass is the average of the isotopic masses that exist based on its abundance

22. Diagrams
Two types of diagrams are used to show the configuration of electrons in an atom

23. Bohr
Shows all electrons in their different energy levels
Dot
Shows only the valence electrons
(outermost energy level

24. Bohr Diagram Find your element on the periodic table
Determine the number of electrons- It is the same as the atomic number for a neutral atom

25. Bohr Diagram
Determine the number of energy levels it is the number of rows down the table

26. Bohr Diagram Higher energy levels hold more elctrons
1st energy level holds 2 electrons
2nd energy level holds 8 electrons
This gives the periodic table its shape

27. Bohr Diagrams
The electrons are represented by dots or the letter e, filling from inside out
The number of energy levels are represented by rings

28. Dot Diagram
Only the number of valence electrons are shown

29. Dot Diagram
Determine the Group number and Determine the number of valence electrons
Draw the dots around the symbol

30. Dot Diagrams
Dots represent the valence e-.
EX: Sodium
EX: Chlorine

31. Metallic Character
Metals
Nonmetals
Metalloids

32. Bellwork 10/19 Who arranged the PT by increasing atomic mass?
Who arranged the PT by increasing atomic number?
What are the vertical columns called?
What are the horizontal rows called?
Does a group or period give you the number of valence electrons? The number of energy levels?
Where are the metals located? Nonmetals? Metalloids?
What are some characteristics of Metals? Nonmetals?

33. Metals Located to the left of the “staircase” Physical Properties
Luster – shiny
Malleable – pounded into different shapes
Ductile – stretched into wires
Solid at room temperature (except Mercury)
Good conductors of heat and electricity

34. Metals Continued Chemical Properties:
Corrosive – gradual wearing away of a metal due to a chemical reaction
Metal converted into a metallic compound
Often lose electrons in a chemical reaction

35. Nonmetals Located to the right of the “staircase” Physical Properties:
Dull in appearance
Brittle – breaks apart easily
Most are gasses at room temperature
Poor conductor of heat and electricity

36. Nonmetals Continued Chemical Properties React with metals
Gain Valence electrons
Elements with 8 valence electrons do not react with other elements

37. Metalloids Border the “staircase”
Have properties of both metals and nonmetals

38. Reactivity
Chemical reactivity is a measure of how easily a substance combines with another substance

39. Reactivity It is related to bonding- oxidation
An oxidation number of 0 has a filled orbital (it is already stable)
Low oxidation number (+-1) are less energy than high ones(+-4)

40. Reactivity Metals and nonmetals are more reactive
Reactivity for metals increase as you move left and down the periodic table
Reactivity for nonmetals increase as you move right and up

41. Periodic Trends

42. Reactivity More reactive metal: Mg or Al?
More reactive Metal: Na or Fr?
More reactive Non-metal: B or O?
More reactive Non metal: F or Br?