+ Chemical Bonding Chm and Cu N 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 Bonding Between metal atoms Overlapping of outer orbitals Sharing of all valance e- between all atoms “sea of electrons” Reason for conductivity

+ Types of Chemical Bonds 2. Ionic Bonding Bond between ions Attraction between + cation and – anion Metals lose e- = cations Nonmetals gain e- = anions

+ Ions Cations (+ charged) Metals become cations Lose valance e- to become stable The octet rule Chemical stability = 8 valance e-

+ Ions Anions (- charged) Non-Metals become anions Gain 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 Bonds Between nonmetal atoms Overlap of outer orbitals valance e- are shared Each atom can achieve stability 8 valance e- 2 valance e- (Hydrogen) 6 valance e- (Boron)

+ Covalent Bonding

+ Types of Covalent Bonds 1. Nonpolar Covalent Bonds e- are being shared equally no electronegativity difference between atoms ( Δ EN < 0.3) least ionic character diatomic molecules atoms that cannot exist alone Always exist bonded to themselves

+ Types of Covalent Bonds 2. Polar Covalent Bonds e- are not being shared equally Larger electronegativity difference between atoms ( Δ EN > 0.3) Higher ionic character Results in + and – partial charges on atoms * Bonds with Δ EN > 1.7 = ionic bonds (100% ionic character)

+ Non Polar Covalent Bond

+ Polar Covalent Bond δ δ δ