ap化学课件共价键粘合甲烷ch4键合模型并非现实每个都有其自身.pdf

Covalent

Bonding

Bondingmodelsfor

methane,CH.Modelsare

4

NOTreality.Eachhasits

ownstrengthsand

limitations.

CovalentBonds

Polar-Covalentbonds

▪Electronsareunequallyshared

▪Electronegativitydifferencween.3

and1.7

Nonpolar-Covalentbonds

▪Electronsareequallyshared

▪Electronegativitydifferenceof

0to0.3

CovalentBondings

❑Electron–electronrepulsives

❑Proton–protonrepulsives

❑Electron–protonattractives

BondLengthandEnergy

BondlengthBondEnergy

BondBondtype(pm)(kJ/mol)

C-CSingle154347

C=CDouble134614

C”CTriple120839

C-OSingle143358

C=ODouble123745

C-NSingle143305

C=NDouble138615

C”NTriple116891

Bondsbetweenelementseshornd

strongerasmultiplicityreases.

BondEnergyandEnthalpy

DH=Dbondsbroken-Dbondsformed

EnergyrequiredEnergyreleased

D=Bondenergypermoleofbonds

Breakingbondsalwaysrequiresenergy

Breaking=endothermic

Formingbondsalw