Introduction to Bonding

Vocabulary Chemical Bond attractive force between atoms or ions that binds them together as a unit bonds form in order to… decrease kinetic energy (KE) increase stability

NaCl CO2 Vocabulary CHEMICAL FORMULA IONIC COVALENT Metal + Nonmetal

NaNO3 NaCl Vocabulary COMPOUND 1 2 3 1 2 more than 2 elements Binary Compound Tertiary Compound 1 2 3 1 2 NaNO3 NaCl

NO3- Na+ Vocabulary ION 1 2 1 1 type of atom 2 or more type of atoms -a charged particle ION -results when an atom gains or loses e-’s 1 type of atom 2 or more type of atoms Monatomic Ion Polyatomic Ion 1 2 1 NO3- Na+

A. Energy of Bond Formation Potential Energy based on position of an object low PE = high stability

A. Energy of Bond Formation Potential Energy Diagram attraction vs. repulsion no interaction increased attraction

A. Energy of Bond Formation Potential Energy Diagram attraction vs. repulsion increased repulsion balanced attraction & repulsion

A. Energy of Bond Formation Bond Energy Energy required to break a bond Bond Energy Bond Length

A. Energy of Bond Formation Bond Energy Short bond = high bond energy

Types of Bonds IONIC COVALENT Bond Formation e- are transferred from metal to nonmetal e- are shared between two nonmetals Type of Structure crystal lattice true molecules Physical State solid liquid or gas Melting Point high low Solubility in Water yes usually not Electrical Conductivity yes (solution or liquid) no Other Properties Metal + Nonmetal Nonmetal + Nonmetal

Ionic Bonding - Crystal Lattice Types of Bonds Ionic Bonding - Crystal Lattice

A. Energy of Bond Formation Lattice Energy Energy released when one mole of an ionic crystalline compound is formed from gaseous ions

Covalent Bonding - True Molecules Types of Bonds Covalent Bonding - True Molecules Diatomic Molecule

Bond Polarity Electronegativity Attraction an atom has for a shared pair of electrons. higher e-neg atom  - lower e-neg atom +

Bond Polarity Electronegativity Trend Increases up and to the right.

Bond Polarity Nonpolar Covalent Bond e- are shared equally symmetrical e- density usually identical atoms

+ - Bond Polarity Polar Covalent Bond e- are shared unequally asymmetrical e- density results in partial charges (dipole) + -

Electrons are transferred from metal to nonmetal. Ionic Bond Electrons are transferred from metal to nonmetal. The metal will lose e- and become + The nonmetal will gain e- and become - Metal Nonmetal

Bond Polarity Nonpolar Polar Ionic

Bond Polarity Examples: Cl2 HCl 3.0-3.0=0.0 Nonpolar 3.0-2.1=0.9 NaCl 3.0-0.9=2.1 Ionic