1. The Periodic Table of the Elements

2. Mendeleev’s Arrangement
Mendeleev arranged the elements based on mass. What he found was a pattern of valence numbers.
Valence number is the number of electrons involved in chemical bonds.
1,2,3,4,3,2,1,0

3. Mendeleev’s Prediction

4. Modern Periodic Table
Periodic Law – elements are arranged by increasing atomic number.
Properties of elements repeat in a predictable way when atomic numbers are used to arrange element into groups

5. Modern Periodic Table
Periods
Groups or Families

6. Chemical Families Alkali Metals – Group1
Alkaline Earth Metals – Group 2
Transition Metals – Groups 3 through 12
Boron Family – Group 13
Carbon Family – Group 14
Nitrogen Family – Group 15
Oxygen Family – Group 16
Halogens – Group 17
Nobel Gases – Group 18

7. Trends on the Periodic Table
Atomic Number
Atomic Mass
Number of Valence Electrons
Size of the atoms / Number of electron shells
Metallic to Non-metallic
Reactivity