The Periodic Table

History of the Periodic Table Solving the Periodic Puzzle  Created by Dmitri Mendeleev in late 1800s  Organized according to increasing atomic mass  Reorganized by Henry Mosley in 1913  Organized by increasing atomic number from left to right and by changes in physical and chemical properties going down a group

Original Periodic Table

Organization of the Periodic Table Groups or Families  Numbered 1 through 18  Vertical columns  Elements in each group have similar chemical and physical properties  Elements in each group have the same number of valence electrons Periods  Numbered 1 through 7  Horizontal rows  Increase by 1 proton and 1 electron as you go from left to right  Increase in mass number as you go from left to right  Increase in atomic number as you go from left to right

 The Element Song (Original) The Element Song (Original)  Sheldon Cooper Singing the Element Song Sheldon Cooper Singing the Element Song

Types of Elements

Characteristics of Metals  Good conductors of heat and electricity  All but one is solid at room temperature  Exception is Mercury – liquid at room temperature  Reflects light (luster), malleable and ductile  Generally has 1 to 3 electrons in their outer energy levels  Tends to give up or lose electrons in bonding

Characteristics of Nonmetals  Located on the right hand side of the Periodic Table  17 elements (including Hydrogen)  Usually are gases or brittle solids at room temperature  If solid at room temperature – not malleable or ductile  Does not conduct heat or electricity well  Not shiny  Tends to gain or share electrons when bonding

Characteristics of Metalloids  Elements: B, Si, Ge, As, Sb, Te, At  Characteristics of metals and nonmetals  Can be shiny or dull  Average conductors of heat and electricity  Mixed in with metals and nonmetals in groups 13 through 17

Diatomic Molecules  Elements that are bonded to each other in nature  Hydrogen (H 2 ), Oxygen (O 2 ), Bromine (Br 2 ), Chlorine (Cl 2 ), Fluorine (F 2 ), Iodine (I 2 ), Nitrogen (N 2 )

Families/Groups of the Periodic Table  Alkali Metals – Group 1 (except H)  Most reactive metals  Alkaline Earth Metals – Group 2  Transition Metals – Group 3 – 12  Halogens – Group 17  Most reactive nonmetals  Noble Gases – Group 18

Series of the Periodic Table  Lanthanide Series  Rare Earth Metals  Elements #  Actinide Series  Tend to be unstable and radioactive  Elements #93 and all above #95 can only be produced in a laboratory

How are properties of elements organized on the Periodic Table?  Within a group  Chemical and physical properties are similar but not identical  Within a period  Properties vary according to the group