Chemical BondingChemical BondingIonic and MetallicIonic and Metallic

ChemistryChemistry

ElementsElements Some elements never Some elements never

exist by themselvesexist by themselves These are called diatomic These are called diatomic

moleculesmolecules There are seven of them There are seven of them

and they make a seven on and they make a seven on the periodic tablethe periodic table

The Diatomic MoleculesThe Diatomic Molecules These would still be said These would still be said

by their elemental name by their elemental name but would be written with a but would be written with a subscript of 2subscript of 2

HH22 NN2 2

FF22 OO2 2

II2 2

ClCl22 BrBr2 2 BrINClHOFBrINClHOF

CompoundsCompoundsMost elements are not found separately Most elements are not found separately

but combined in a compound with but combined in a compound with something elsesomething else

Chemical bonds are strong attractions Chemical bonds are strong attractions between atoms or ions in a compoundbetween atoms or ions in a compound

The reason for this is the octet ruleThe reason for this is the octet rule

We want 8…eight is great!

Octet RuleOctet Rule Noble gases are what Noble gases are what

all elements aspire to all elements aspire to be like electronicallybe like electronically

These elements have These elements have 8 electrons in highest 8 electrons in highest energy levelenergy level

Ionic BondIonic BondDEFINITION:DEFINITION:Chemical bond formed by the electrostatic Chemical bond formed by the electrostatic attraction between a cation and an anion.attraction between a cation and an anion.Atoms will either give up or take electrons Atoms will either give up or take electrons in order to have eight in their highest energy in order to have eight in their highest energy levellevel

Hey, can you help me out

and gimme an electron?

Why certainly, I have one I don’t want anyway.

Give up/take away electronsGive up/take away electrons

ChargesChargesSodium now has a +1 charge since it has Sodium now has a +1 charge since it has

lost an electronlost an electronChlorine now has a -1 charge since it Chlorine now has a -1 charge since it

gained an electrongained an electron

Ionic CompoundIonic CompoundThe combination of NaThe combination of Na++ and Cl and Cl-- form the form the

compound NaClcompound NaClAn ionic compound will always consist of:An ionic compound will always consist of:

A metal ion (called a CATION, the + one)A metal ion (called a CATION, the + one)A non-metal ion (called an ANION, the - one)A non-metal ion (called an ANION, the - one)

CATION ALWAYS COMES BEFORE THE CATION ALWAYS COMES BEFORE THE ANION; both in the name and the formulaANION; both in the name and the formula

CATION vs ANIONCATION vs ANION Positively charged Positively charged

ionsions Lose electronsLose electrons Smaller than the Smaller than the

parent atomparent atom Usually metals (left Usually metals (left

side of the table)side of the table)

Negatively charged Negatively charged ionsions

Gain electronsGain electrons Larger than the Larger than the

parent atomparent atom Usually nonmetals Usually nonmetals

(right side of table)(right side of table)

Properties of Ionic BondsProperties of Ionic Bonds

1.1. High melting pointHigh melting point2.2. Conducts electricityConducts electricity3.3. Soluble in waterSoluble in water

Lewis Dot DiagramsLewis Dot DiagramsDiagram that shows the valence electronsDiagram that shows the valence electronsShows ions or compounds or atomsShows ions or compounds or atoms

Metallic BondsMetallic BondsDEFINITION:DEFINITION:Attraction of free floating valence electrons Attraction of free floating valence electrons

for the positively charged metal cations.for the positively charged metal cations.

“Sea of electrons”

Properties of Metallic BondsProperties of Metallic Bonds

1.1. Malleable/DuctileMalleable/Ductile2.2. Conduct electricity and heatConduct electricity and heat3.3. Solid at room temp and shiny lusterSolid at room temp and shiny luster