Ch. 6 Chemical Bonding What type of atom is stable or neutral in nature? Noble Gases – outer energy level is satisfied What is a chemical bond? An attraction between two atoms that combine to become more stable.

2 Types of Chemical Bonds 1. Ionic Bond – a forced attraction between positive and negative ions. The atom either gains or loses electrons. Ex. Na + Cl 2. Covalent Bond – a bond that results in sharing electrons. Electrons are shared between atoms. Ex. Cl2

Polar vs. Nonpolar Molecules Polar Molecules – atoms with opposite charges that combine. Ex. Ionic bonds & some covalent bonds Nonpolar Molecules – atoms with alike charges that combine. Ex. Covalent bonds

What is the smallest unit quantity of matter which can exist by itself and retain all the properties of the original substance. Molecule There is at least 1 atom for each molecule. A molecule that contains 2 atoms of the same element is called? Diatomic Molecule Molecular Formula shows the types and numbers of atoms combined in a single molecule.

C, H, and O make up over 90% of all the known compounds. Bond energy is the energy needed to break a chemical bond and form neutral atoms. Ex. Pg. 168 The bond energy is higher as the bond length becomes shorter. Octet Rule – states that chemical compounds tend to form so that each atom, by gaining, losing, or sharing electrons, has an octet of electrons in its highest occupied energy level. (Use Dot Diagram)

Lewis Dot Structures are formulas with atomic symbols and inner-shell electrons, dot-pairs or dashes between 2 atomic symbols represent electron pairs. Examples??? Structural Formula – indicates the type of bond between atoms. Single bond – sharing of 1 pair of electrons between 2 atoms.

Double bond – sharing of 2 pair of electrons between atoms. Triple bond – sharing of 3 pair of electrons between atoms. Sample Problems  6-2, 6-3, 6-4 Polyatomic Ion – is a charged group of atoms. Ex. OH-, NH4+

Ionic Compound – is composed of positive & negative ions combined so that positive and negative charges are equal. Ex. Na + Cl  NaCl Ionic compounds are usually crystal structure Formula Unit – a collection of atoms from which a compound’s formula can be established. Ex. Ca2+ + F-  CaF2

Metallic Bonding Metallic bonds are chemical bonds resulting from the attraction between positive ions & surrounding mobile electrons. Bonds between metals Electrons flow easier  metals are more rigid. Malleability – ability to roll metals into sheets. Ductility – ability to draw metals into wire

VSEPR Theory VSEPR theory states the electrostatic repulsion between the valence-shell electron pairs surrounding an atom causes these pairs to be oriented as far apart as possible. Pg. 186  Table 6-5 Sample Problems 6-5, 6-6