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 Name Valence Number

Oxidation Number

1 Alkali Metals 1 +1

2 Alkaline Earth Metals

2 +2

3 -12 Transitional Elements

1 or 2 ----

13 Boron family 3 +3

14 Carbon family 4 +4 or -4

15 Nitrogen family

5 -3

16 Oxygen family

6 -2

17 Halogens 7 -1

18 Noble Gases 8 0

3 Types of Chemical Bonds

1. Ionic Bonds2. Covalent Bonds3. 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 forcesHigh melting and boiling pointsHard, not easily crushedConduct when melted or dissolved

Covalent compounds

Weaker forces between compoundsLower melting and boiling pointsVolatile liquids and gasesSofter – easily crushedNot conductors

IonicCharged particles carry current

Lit bulb

CovalentNo charged particles

Unlit bulb

Properties of metals

LusterConductorsMalleableDuctile

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 OnlyRepresent The Outer Shell OnlyNever More Than 8 ElectronsNever More Than 8 ElectronsUsed To Show How And Why Used To Show How And Why Elements Combine With Each Elements Combine With Each OtherOther