1. Periodic Table of Elements
The Periodic Law
Periodic Table of Elements

2. Development of the Periodic Table
Dmitri Mendeleev developed the first periodic table
The periodic table is an arrangement of elements according to their chemical and physical properties

3. Mendeleev’s Periodic Table
Mendeleev arranged the elements according to their atomic masses
The elements followed a pattern of 1 +, 2+, 3+, 4+/- , 3-, 2-, 1-, 0 (valence electrons)
video

4. Questions Who developed the first periodic table?
What is the periodic table?
What are valence electrons?
How did Mendeleev arrange elements in the first periodic table?

5. Periodic
Refers to repeating according to a pattern

6. Questions
Why are the days of the week and the months of the year periodic?

7. Modern Periodic Table video
Henry Moseley determined the atomic number of the elements
Elements in the modern periodic table are arranged according to atomic numbers
video

8. Periodic Law
States that the physical and chemical properties of elements are periodic functions of their atomic numbers
Properties of elements have some pattern according to their atomic numbers

9. Questions
What is the major difference between Mendeleev’s periodic table and the modern periodic table?

10. Columns in the periodic table
Columns of elements are known as groups or families
Elements in a family have similar properties

11. Rows in the periodic table
The horizontal rows of elements are called periods
The elements in a period do NOT have similar properties

12. Periods
First element in a period is an active solid
Last element in a period is an inactive gas

13. Questions
What is the major difference between periods and families?
How are elements in a family similar?
How are elements in a period different?

14. Element squares in the periodic table
The basic information found in each square of the periodic table :
Atomic number
Chemical symbol
Element name
Atomic mass
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15. Elements
Elements are classified as:
Metals
Nonmetals
Metalloids

16. Questions
What information is found in the squares on the periodic table?
How can an element be classified?

17. Characteristics of Metals (video)
Good conductors of heat and electricity
Shiny; High melting points
Malleable (bends easily)
Ductile (can be made into wires)
Found on the LEFT of the periodic table

18. Questions
What is the difference between ductile and malleable?
Where are metals found on the periodic table?

19. Properties of Nonmetals
Dull
Brittle (hard/ easily broken)
Found on the RIGHT of the periodic table
video

20. Properties of Metalloids
Has properties of both metals and nonmetals
Found touching the dark, zig-zag line
Metalloid means “metal-like”
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21. Questions
What is a metalloid?
Where are metalloids located in the periodic table?
Where are nonmetals located on the periodic table?

22. Summary Slide
Periodic Properties of Elements (Modern Table)

23. Periodic Properties of Elements (Modern Table)
Valence pattern across a period is:
First 4 columns lose
Last 4 columns gain
(left to right)
Metals lose electrons easily
Nonmetals gain electrons easily

24. Periodic Properties of Elements
The size of the atom decreases from left to right across a period
The metallic properties of elements decrease from left to right across a period
Elements on the left are more reactive than the elements on the right

25. Questions
What happens to metallic properties as one moves from left to right across a period?
What is the valence pattern of electrons across a period?
video