+

Chemical Bonding

Chm 1.2.1 and 1.2.2

CuN

ArF

+Chemical Bond

A mutual attraction for electrons on adjacent atoms

Atoms bond in different ways in order to achieve stability

Stability = lowest energy

e- involved in bonding = valance e-

+Valance Electrons

e- in the outermost energy level (n)

Determined by electron configuration

Determined by group #s block valance e- = group #p block valance e- = group # - 10

d and f block = 2 valance e-

+Types of Chemical Bonds

1. Metallic BondingBetween metal atomsOverlapping of outer orbitalsSharing of all valance e- between all atoms

“sea of electrons”Reason for conductivity

+Types of Chemical Bonds

2. Ionic BondingBond between ions Attraction between + cation and – anion

Metals lose e- = cationsNonmetals gain e- = anions

+Ions

Cations (+ charged)Metals become cationsLose valance e- to become stable

The octet rule Chemical stability = 8 valance e-

+Ions

Anions (- charged)Non-Metals become anionsGain valance e- to become stable

The octet rule Chemical stability = 8 valance e-

+Ionic Charge

+Ionic Bond: e- transfer

+Types of Chemical Bonds

3. Covalent BondsBetween nonmetal atomsOverlap of outer orbitals valance e- are sharedEach atom can achieve stability8 valance e-2 valance e- (Hydrogen)6 valance e- (Boron)

+Covalent Bonding

+Types of Covalent Bonds1. Nonpolar Covalent Bonds

e- are being shared equallyno electronegativity difference between atoms (ΔEN < 0.3)

least ionic character diatomic molecules

atoms that cannot exist aloneAlways exist bonded to themselves

+Types of Covalent Bonds2. Polar Covalent Bonds

e- are not being shared equallyLarger electronegativity difference between atoms (ΔEN > 0.3)

Higher ionic characterResults in + and – partial charges on atoms

* Bonds with ΔEN > 1.7 = ionic bonds (100% ionic character)

+Non Polar Covalent Bond

+Polar Covalent Bond

δ

δ

δ