CHAPTER SIX – CHEMICAL BONDING SOUTH LAKE HIGH SCHOOL SCIENCE DEPARTMENT MS. SANDERS Chemistry

Electronegativity Figure 2 Page 176 – Difference in Electronegativity: Used to determine what type of bond atoms will make. Subtract the electronegativities. Electronegativity found on page 161.

Electronegativity Practice Page 177 – Classify the bonding between:  Chlorine and Calcium  Cl  Ca

Electronegativity Practice Page 177 – Classify the bonding between:  Chlorine and Oxygen  Cl  O

Electronegativity Practice Page 177 – Classify the bonding between:  Chlorine and Bromine  Cl  Br

Bonding Basics  Chemical bond – mutual electrical attraction ◦ Most atoms at high potential energy as independent particles ◦ Atoms are less stable by themselves ◦ PE is decreased when atoms bond ◦ Bonding is rarely purely ionic or covalent

Bonding Basics  Ionic – transfer electrons; between a cation and an anion (metal and nonmetal)  Covalent – share electrons; between two nonmetals

Bonding Basics Covalent Bonding  Single Bond – two electrons; one line  Double Bond – four electrons; two lines  Triple Bond – six electrons; three lines

Bonding Basics Resonance Structures:  Refers to bonding in molecules or ions that cannot be correctly represented by a single Lewis Structure.  Involves multiple bonds (double or triple bonds)  Examples:  O ₃  SO ₂

Bonding Basics  Metallic – sea of electrons, excellent conductors of electricity, overlapping of orbitals creates mobility for electrons, absorb and reflect light ◦ Malleability – to be beaten into sheets ◦ Ductility – to be drawn into wires ◦ Conducts heat and electricity

VSEPR Valence-shell, electron-pair repulsion Refers to the repulsion between pairs of valence electrons of the atoms in a molecule Causes the valence electrons to be as far apart as possible Accounts for the molecular shapes of molecules

VSEPR VSEPR and Molecular Geometry:

VSEPR VSEPR and Molecular Geometry:

Intermolecular Forces Force of attraction between molecules Generally weaker than intramolecular forces (ionic & covalent)

Intermolecular Forces Types:  Dipole-Dipole:  Force of attraction between polar molecules  Only acts on nearby molecules  Hydrogen Bonds:  Strongest of intermolecular forces  H atom is bonded to a highly electronegative atom and weakly bonded to an unshared electron pair  London Dispersion Forces:  The weakest  Caused by the movement of electrons  Noble gas atoms and nonpolar molecules

Intermolecular Forces Dipole-Dipole: Hydrogen Bond: London Dispersion Forces: