The Periodic Table Created by Mendeleev Lists all elements known to humans. Everything in the universe is made up of these ‘building blocks’.

The Periodic Table Metals on the left Non-Metals on the right Separated by the “staircase” Metalloids have properties of both Refer to back in text

The Periodic Table Metals are – shiny, malleable, good conductors, and mostly solids (at room temp.) React with acid Non-Metals – dull, brittle, insulators, can be solids liquids or gases Do not react with acid

Trends in the Periodic Table Rows (“Periods”)  tells you how many orbits/shells that element has Column (“Families”)  Tells you how many valence electrons that element has note: transition metals are exception to the rule

Trends

Chemical Families Alkali Metals – 1st column (Li, Na, K, etc.) Shiny silvery metals, make soluble compounds Alkaline Earth Metals – 2nd column (Mg, Ca, Ba, etc.) Shiny silvery metals, make non-soluble compounds

Chemical Families Halogens – 7th column (F, Cl, Br, etc.) Poisonous and reactive. Noble Gases – 8th column (He, Ne, etc.) Tend not to form compounds. Not reactive.

Look at periodic table How many electrons total do these elements have? a) Li b) N c) Cl How many valence electrons do these elements have? a) O b) Be c) Al d) Ar How many shells/orbits do these elements have? a) Mg b) He c) P d) Ne 5 17 3 3 6 4 8 1 3 2 3

Forming Compounds

Forming Compounds Atoms are rarely in their ‘stable’ form Only the noble gases. Usually atoms obtain a full valence shell by bonding (gaining and loseing e-) Atoms bond to other atoms to make Molecules (a.k.a. Compounds)

Forming Compounds 2 Types 1) Ionic molecules – electron are transferred between molecules to complete valence shells. 2) Covalent molecules – electrons are shared to complete valence shells.

Ionic Bonding

Ionic Compounds Between a metal and a non-metal Ex. NaCl, MgCl2 , AlF3 Electrons are transferred from the metal to the non-metal. “Ions” (charged atoms) become formed. Ions attract each other and are ‘bonded’ together forming IONIC BONDS.

How do Sodium and Chlorine Bond? Draw both elements apart (Bohr Diagram) Electrons get transferred to give each atom a full valence shell (charged ions) The molecule has an overall charge (add all charges together) +1 – 1 = 0 Na 11p 12n Cl 17p 18n +1 -1 Na 11p 12n Cl 17p 18n

How do Lithium and Oxygen Bond? Draw both elements apart (Bohr Diagram) Electrons get transferred to give each atom a full valence shell (charged ions) (You can add more Li or O if needed) The molecule has an overall charge (add all charges together) +1 +1 – 2 = 0 Li 3p 3n O 8p 8n +1 -2 +1 Li 3p 3n O 8p 8n Li 3p 3n

How do Calcium and Chlorine Bond? Draw both elements apart (Bohr Diagram) Electrons get transferred to give each atom a full valence shell (charged ions) (You can add more Ca or Cl if needed) The molecule has an overall charge (add all charges together)

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