1. The Periodic Table Chapter 12 Arranging the Elements Section 1

2. What is Periodic? periodic - has a regular, repeating pattern
examples:
Mondays occur once every 7 days…so do Fridays!
Leap year occurs once every four years
The sun rises each day and sets each night
Your birthday occurs once per year

3. Periodic Table
periodic table - chart that organizes and displays the elements by their physical and chemical characteristics
A great deal of information about an element can be gathered from its position in the period table!

4. Mendeleev In 1869, Dmitri Mendeléev created the
first accepted version of the periodic table.
He grouped elements according to their atomic mass, and as he did, he found that the groups had similar chemical properties. 
Blank spaces were left open to add the new elements he predicted would occur. 

5. Changing the Arrangement
Mendeleev noticed that a few elements in the table that were not in their correct place according to their properties.
Incorrect atomic mass perhaps?
In 1914, a 26 year old British scientist named Henry Moseley solved the mystery.

6. Henry Moseley figured out the number of protons = the atomic number
rearranged the elements by atomic number and every element fell into it’s proper place in the improved periodic table

7. Periods horizontal row = period properties are NOT alike
first element in a period is always an extremely active solid
last element in a period, is always an inactive gas

8. Groups columns = groups similar but not identical properties
example: lithium (Li), sodium (Na), potassium (K), and other members of Group 1 are all soft, white, shiny metals
sometimes a group is called a family

10. Found to the left of the zig-zag line
Properties of Metals
BrainPop
Metals
Found to the left of the zig-zag line
good conductors
shiny
solid at room temperature (except mercury - liquid)
ductile (can be stretched into thin wires)
malleable (can be bent and pounded into various shapes)

12. Properties of Non-Metals
Found to the right of the
zig-zag line
poor conductors
NOT ductile or malleable
dull
most are gases at room temperature
solid non-metals are brittle and break easily

14. Properties of Metalloids
Found on both sides of the
zig-zag line
metal – like
properties of both metals and non-metals
semiconductors
solid at room temperature
shiny or dull
ductile
malleable