Chapter 8 Allison Kim Eunwoo Kim Esther Park

Lewis Structure shows how valence electrons are arranged among the atoms in the molecules Only the valence electrons are included in Lewis Structure.

Octet Rule Atoms tend to gain, lose, or share electrons until they are surrounded by eight valence electrons. Exceptions: – Molecules containing odd number of electron – Molecules in which an atom has fewer than an octet of valence electrons – Molecules in which an atom has more than an actet of valence electrons

Ionic Bonding Attraction between ions of unlike charge = stable ionic compounds Lattice energy – energy required to completely separate a mole of a solid ionic compound into its gaseous ions – Lattice energy increase as the charges in the ions increase and as their radii decrease.

Covalent Bonding Results from the sharing of electrons between two atoms – Single bond: one pair of electrons is shared – Double: two pairs of electrons are shared – Triple: three pairs of electrons are shared

Bond Polarity & Dipole Moments Dipole – distance separates two electrical charges of equal magnitude but opposite sign Dipole moment – quantitative measure of the magnitude of a dipole

Electronegativity The ability of an atom in a molecule to attract shared electrons to itself Ionization energy – measures how strongly a gaseous atom holds on to its electrons Electron affinity – measure of how strongly an atom attracts additional electrons

Formal Charge Formal Charge – charge the atom would have if all the atoms in the molecule had the same electronegativity

Resonance Structures Occurs when more than one valid Lewis structure can be written for particular molecule

Strengths of covalent bonds