The Periodic Table of the Elements

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

Mendeleev’s Prediction

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

Modern Periodic Table Periods Groups or Families

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

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