1. THE PERIODIC TABLE and PERIODIC LAW

3. Essential Questions * How can we organize all the different elements?
* How can the periodic table help us organize
our chemistry knowledge?
* What can we predict about elements based
on their classification &location on the
periodic table?

4. II. WHY IS THE PERIODIC TABLE IMPORTANT?

5. WHAT DOES THE WORD “PERIODIC” MEAN?
A. DEFINITION--
Happening or repeating at regular intervals
Cyclic - happening in a cycle
B. EXAMPLES OF OTHER EVENTS
THAT ARE PERIODIC--
Phases of moon
Seasons
Tides

6. IV. HISTORICAL DEVELOPMENT OF THE PERIODIC TABLE

7. How was the Periodic Table developed?
Done by many scientists

8. Dobereiner 1829 Tried to arrange elements in groups of three
Based on Dalton's atomic theory
Not very successful

9. Newland
1864
Found that when arranged by mass, the eighth element was similar in physical and chemical properties
Related it to a musical scale
Called Newland's octaves

10. DMITRI MENDELEEV Why is he considered the
“Father of the Periodic Table”?

11. LOTHAR MEYER
Worked at the same time as Mendeleev.
Both men demonstrated a connection between atomic mass and properties of elements.
However, Mendeleev given more credit.
WHY???
He Published First!

12. Giant Wall Periodic Table erected in St. Petersburg, Russia in 1934
Why the blanks?
Giant Wall Periodic Table erected
in St. Petersburg, Russia in 1934

13. ORGANIZATION OF MENDELEEV’S TABLE

14. LEFT BLANKS
Mendeleev left spaces on the table where
he thought undiscovered elements should go.
4. ORIGINAL PERIODIC LAW--
The physical and chemical properties of elements
are periodic functions of their atomic mass.

15. 5. MODIFICATION OF PERIODIC LAW
Locate several elements on the current table
that are not arranged according to increasing
atomic mass.
Co & Ni 58.69
Examples:
Te & I
Th & Pa
U & Np
Mendeleev’s table not completely correct.

16. HENRY MOSELEY

17. In 1913, Henry Mosely discovered that atoms
of each element had a unique atomic number.
2. Arranged elements by
atomic number, not atomic mass.
3. Eliminated problems from Mendeleev's table

18. MODERN PERIODIC LAW-- STATES THAT WHEN THE ELEMENTS ARE
ARRANGED BY INCREASING ATOMIC
NUMBER, THERE IS A PERIODIC
REPETITION OF THEIR CHEMICAL
AND PHYSICAL PROPERTIES

19. ELEMENTAL INFORMATION ON THE PERIODIC TABLE
READING SQUARES OF THE
PERIODIC TABLE
35.45 Cl 17
chlorine
mass
Atomic #

20. Squares of the Periodic Table

21. VI. ORGANIZATION OF THE PERIODIC TABLE A. PERIODS 1. Definition--
--a horizontal row of elements on the
Periodic Table
--also called a “Series”
2. Energy levels and periods--
--the number of the period is equal to the
number of “rings” of electrons around the atom
**How many energy levels are in each element in Period 5?

22. B. GROUPS
1. Definition--
--a vertical column of elements on the Periodic
Table
--also called a “Family”
2. Valence electrons and group number--
--each element within a group has the same
number of valence electrons
--In general, the group number is equal to the
number of valence electrons
--For group numbers greater than 10, the number
of valence electrons is the ones place

23. **How many valence electrons are in Group 2 elements?
B. GROUPS
**How many valence electrons are in Group 2 elements?
**How many valence electrons are in Group 16 elements?

24. 3. CLASSIFYING THE ELEMENTS

25. a. Alkali Metals--
Group 1 elements except Hydrogen.
Most reactive metals on the Table.
Have 1 valence electron.

26. Have 2 valence electrons.
b. Alkaline Earth Metals--
Group 2 elements.
Very active metals.
Have 2 valence electrons.

27. c. Transition Metals--
Groups 3-11 elements.
Typically less reactive than Alkali and
Alkaline Earth Metals.
Produce colored solutions.

28. d. Halogens--
Group 17 elements.
Most nonmetallic elements
on the table.
Have 7 valence electrons

29. Have 8 valence electrons except He which has only 2.
e. Noble Gases--
Group 18 elements.
Extremely unreactive.
Often called “inert”.
Have 8 valence electrons except
He which has only 2.

30. f. Two Rows at the Bottom--
Lanthanide Series--
Elements 57 – 71.
Actinide Series--
Elements

32. VII. PERIOIDIC TRENDS As we can see, elements are grouped on the
Periodic Table according to their physical and
chemical properties as well as their electron
configurations.
This creates the periodic repetition on the table, and allows us to see certain trends in these properties.

33. Trends on the Table Atomic radius Ionization energy Electronegativity
Each of these show trends as you move across a period AND down a group

34. Major Element Grouping
The combination of periodic characteristics creates three broad categories of elements on the table:
Metals
Nonmetals
Metalloids

35. Major Element Grouping
Described in relationship to the staircase that runs on the right-hand side of the table
Elements to the RIGHT of the staircase = NONMETALS
Elements to the LEFT of the staircase = METALS
Elements touching staircase (except Al) = METALLOIDS

36. F. Metallic and Nonmetallic Properties
Can help us characterize an element simply
by knowing its placement on the PT

37. Metals Lose electrons easily to get to "magic number" of 8
"Metals are losers"
Losing electrons makes them form an ION = charged atom
Most metallic elements = lower left of table

38. Cation-- What is an Ion? REVIEW: A positively charged atom + + + +
An atom that has lost or gained electrons and thus
has acquired a charge.
Cation--
A positively charged atom + +
PLUSSY CATS!! + +

39. Nonmetals Gain electrons easily to get to "magic number" of 8
Nonmetals are "gainers"
Most non-metallic elements - upper right side of table

40. Anion--
A negatively charged atom
"Cat chaser"

41. METAL NONMETAL LOSE GAIN CATION ANION
Gain/lose
electrons
LOSE
GAIN
CATION
ANION
Ion Formed