Bonds, Atomic Bonds

Valence Number  Number of electrons an atom has in its outer energy level.  All atoms want 8 electrons in their outer energy level.  A happy and stable atom has 8 electrons in its outer energy level. 8

Oxidation Number  Number of electrons an atom will gain, lose, or share while bonding with another element.

Group Number Group NameValence Number Oxidation Number 1Alkali Metals1+1 2Alkaline Earth Metals Transitional Elements 1 or Boron family3+3 14Carbon family4+4 or -4 15Nitrogen family5-3 16Oxygen family6-2 17Halogens7 18Noble Gases80

3 Types of Chemical Bonds 1.Ionic Bonds 2.Covalent Bonds 3.Metallic Bonds

Ions Recall that p + have charge +1, e - have charge -1 –# p + = # e - : no net charge = neutral –# p + > # e - : net + charge = Cation –# p + < # e - : net - charge = Anion

Ionic compounds Crystal lattice – strong forces High melting and boiling points Hard, not easily crushed Conduct when melted or dissolved

Covalent compounds Weaker forces between compounds Lower melting and boiling points Volatile liquids and gases Softer – easily crushed Not conductors

Ionic Charged particles carry current Lit bulb Covalent No charged particles Unlit bulb

Properties of metals Luster Conductors Malleable Ductile

Lewis Dot Diagram: Elements Shows the number of electrons in the outer energy level of an atom –“valence electrons”

Electron Dot Diagram Symbol surrounded by dots to represent the valence electrons

LEWIS’ DOT FORMULAS Represent The Outer Shell Only Never More Than 8 Electrons Used To Show How And Why Elements Combine With Each Other