AP Chemistry - Molecular and Ionic Compound Structure and Properties

ionic bonding

transfer of electrons from a metal to a nonmetal, forming cations and anions

covalent bonding

sharing of one or more pairs of electrons between two nonmetals

metallic bonding is between a

metal and metal

How are electrons shared in metallic bonding?

valence electrons are donated into a vast electron pool

Why do metals conduct energy?

delocalization

Why are noble gases stable?

they have a filled valence electron

isoelectronic

having the same number and arrangements of electrons as the closest noble gas

Lewis electron-dot structures

method of representing an element and its valence electrons

Lewis electron-dot structures are not useful for:

transition and inner transition metals

cations

postively charged ions

anions

negatively charged ions

Ionic bonds are formed the

attraction between opposite charges

Atoms lose or gain the amount electrons needed for them to form a

full octet

crisscross rule

the numerical value of the superscript charge becomes the subscript on the other ion

nonpolar covalent bond

bond between two atoms in which the attraction is the same

polar covalent bond

bond between two atoms with different levels of attraction

electronegativity (EN)

measure of the attractive force an atom exerts on a bonding pair of electrons

electronegativities increase from ________ and decrease going __________

left to right; top to bottom

what element is the most electronegative?

flourine

formal charge

charge associated with the most reasonable Lewis structure

formal charge equation

formal charge = (# of valence electrons) - (# of nonbonding electrons - 1/2 # of bonding electrons)

Formal charges of a favorable Lewis structure

small numbers, no like charges adjacent to each other, low formal charges on electronegative elements, totals to the harge on the ion or 0 for a compound

valence-shell electron-pair repulsion theory (VSPER)

valence electrons pairs surrounding a central pair will try to move away from each other to minimize repulsion

electron-group geometry

all electron groups are considered

molecular geometry

only bonding electrons are considered

linear geometry

two bonding pairs

trigonal planar geometry

three bonding pairs

bent geometry

two bonding pairs, one to two lone pairs

tetrahedral geometry

four bonding pairs

trigonal pyramidal geometry

three bonding pairs, one lone pair

trigonal bipyramidal geometry

five bonding pairs

irregular tetrahedral (see-saw) geometry

four bonding pairs, one lone pair

t-shaped geometry

three bonding pairs, two lone pairs

linear geometry (5 pairs)

two bonding pairs, three lone pairs

octahedral geometry

six bonding pairs

square pyramidal geometry

five bonding pairs, one lone pair

square planar geometry

four bonding pairs, two lone pairs

valence bond theory

the mixing of covalent atomic orbitals to form a new kind of orbital

hybrid orbitals

mixed atomic orbitals in covalent bonding

sp hybridization

overlap of an s and p orbital with linear orientation

sp^2 hybridization

overlap of an s orbital and two p orbitals with a trigonal planar orientation

sp^3 hybridization

overlap of an s orbital and three p orbitals with tetrahedral orientation

sigma (σ) bonds

overlap orbitals occuring on a line between atoms involved in covalent bond

pi (π) bonds

overlap of orbitals occuring above and below the line through the two nuclei of the bonding atoms

resonance

more than one Lewis structure can be written for a Lewis structure

how does the actual structure of a molecule compare to its resonance structure?

the actual structure is an average of the resonance structure; all the bonds in the molecule are the same

a bond with a higher order is:

stronger and shorter

paramagnetism

attraction to a magnetic field

diamagnetism

slight repulsion from a magnetic field