Final Exam Review

Chemical bond
Force that holds two atoms together
Bond dissociation energy
Energy required to break a bond
Types of electrons does bonding require the behavior of
Valence electrons (outermost s+p levels)
Ionic Bonding

delta X > 1.7

Involves mixture of (usually) metal and nonmetal

Nonmentals alomst at full valance, therefore want to pull e-

Highest- Fluorine
Lowest- Francium/Cesium

Make a large group of ions…resulting crystal is very sturdy and strong (electrostatic attractions holding it together)

Electronegativity
Tendancy of bonded atoms to pull electrons toward itself
Electronegativity
Tendancy of bonded atoms to pull electrons toward itself
Covalent Bonding

delta x < .5 or 50

Generally occurs w/ two nonmetals

E- on one atom will start to be attracted to nucleus(proton) of other, v.e- lowers energy (attracted forces tend to lower energy of a system)

Potential energy goes up when nuclei gets too close together forming repulsion

chemical potential energy stored in bond

difference between 0 and lowest energy point …but because difference in small to 0, don’t take e- from eachother

Polar Covalent Bonding
Bond is a covalent bond (due to difference in X), but is one in which the electrons are unequally shared

drawing different for covalent bonds

Drawing covalent bonds
1. write skeleton structure of the mlcl
2. find total v. e-, including any charges present
3. connect atomos w/ a single bond (a line which stands for 2e-)
4. fill up octets of outside atom w/ remaining e-
5. a) any extra e- go on center atom, even if has octet
b) if run out of e-; meed to multiple bond
VSEPR
Can find shape of the ion/mlcl formed

shape tells us to dictate how mlcl/ion interacts with other stuff

V = Valence
S = Shell
E = Electron
P = Pair
R = Repulsion

Coordination number
Sum of the # of atoms attached and # of nonbinding (lone) pairs of electrons on the atom

Tells # orbitals need, which tells you # of old orbitals you used up

All atoms positioning themselves to be as far apart as possible
Because surrounded by e- density and lone pairs of e- around a central atom

minimize the repulsion forces between regions of e- density and lone pairs e- more repulsive than atoms (more pushing power)

Coord. # : 2
Lone Pairs : 0
Electron Geo. = linear
Molecular Geo. = linear
(180 degrees)
Ex: BeF2
Coord. # : 3
Lone Pairs : 0
Electron Geo. = trig. planar
Molecular Geo. = trig. planar
(120 degrees)
Ex: BF3
Coord. # : 3
Lone Pairs : 1
Electron Geo. = trig. planar
Molecular Geo. = v-shaped/bnt
( <120 degrees)
Ex: BF2 –
Coord. # : 4
Lone Pairs: 0
Electron Geo. = tetrahedral
Molecular Geo. = tetrahedral
(109.5 degrees)
Ex: CF4
Coord. # : 4
Lone Pairs: 1
Electron Geo. = tetrahedral
Molecular Geo.=trig. pyramid.
(<109.5 degrees)
Ex: CF3-
Coord. # : 4
Lone Pairs: 2
Electron Geo. = tetrahedral
Molecular Geo. = v-shaped/bnt
(<109.5 degrees)
Ex: CF2 2-
Coord. # : 5
Lone Pairs: 0
Electron Geo. = trig. bipyram
Molecular Geo.= trig. bipyram
(120 + 90 degrees)
Ex: SbF5
Coord. # : 5
Lone Pairs: 1
Electron Geo. = trig. bipyram
Molecular Geo. = see-saw
(<120,<90 degrees)
Ex: SbF4 –
Coord. # : 5
Lone Pairs: 2
Ex: SbF3 2-
Electron Geo. = trig. bipyram
Molecular Geo. = t-shaped
(<90 degrees)
Coord. # : 5
Lone Pairs: 2
Ex: SbF3 2-
Electron Geo. = trig. bipyram
Molecular Geo. = t-shaped
(<90 degrees)
Coord. # : 5
Lone Pairs: 3
Electron Geo. = trig. bipyram
Molecular Geo. = linear
(180 degrees)
Ex: SbF2 3-
Coord. # : 6
Lone Pairs: 0
Electron Geo. = octahedral
Molecular Geo. = octahedral
(90 degrees)
Ex: TeF6
Coord. # : 6
Lone Pairs: 1
Electron Geo. = octahedral
Molecular Geo. = sq. pyramid.
( degrees)
Ex: TeF5 –
Coord. # : 6
Lone Pairs: 2
Electron Geo. = octahedral
Molecular Geo. = sq. planar
(<90 degrees)
Ex: Tef4 2-
Hybridization
Behavior of an atom that’s involved in bonding

When they bond, often create new orbitals specifically for bonding (covalent)

Each coordination # has corresponding hybrid., which produces own unique shape

Coord # 2
Hybrid: sp
Shape: linear
Coord # 3
Hybrid: sp2
Shape: trigonal planar
Coord # 4
Hybrid: sp3
Shape: tetrahedral
Coord # 5
Hybrid: sp3d
Shape: trigonal bipyramidal