AP Chemistry test #3

chapters 8 and 9

chemical bond

attractive forces that hold groups of atoms together and make them function as a unit

required

energy is ______ to break a bond

Released

energy is _____ when bonds form

ionic bond

electrostatic attraction between ions

covalent bond

electrons shared (not necessarily equally)

ionic

elements that are far from each other on the periodic table form _____ bonds

ionic

largest electronegativity differences in ____ bonds:

polar covalent

significant electronegative differences in ____ bonds:

non polar covalent

very small electronegative differences or none in ____ bonds:

non polar covalent

H-H and C-H are ____ bonds:

attractions

bonding is based on _____ that exist between charged particles

bond enthalpy

measure of heat released when bond forms (-)or heat required to break a bond (+)

triple bond

high bond strength, short bond length:

single bond

low bond strength, high bond length

transition metals

tend to form +2 ions but their are exceptions

• many form more than 1 cation

nonmetals

gain electrons to become negatively charged ions when forming ionic compounds

metals

lose electrons and become cations

ionic solids

crystalline solid, brittle, high melting points

not enough room

ionic solids are non-conductors because there is ______ for electrons to flow between ions

aqueous solutions and molten

ionic compounds do conduct as:

lattice energy

change in energy when ions in the gaseous state for an ionic solid (-) or the energy required to separate a mol of an ionic solid into gaseous ions (+)

positive

energy required to separate has a ____ value:

negative

energy to form an ionic solid has a ____ value:

covalent bonding

sharing of electrons between 2 atoms

polar

the farther atoms are from each other on the periodic table, the more ____ the covalent bond

boron

happy with 6 electrons

beryllium

happy with 4 electrons

hydrogen

happy with 2 electrons

3rd period

more than 8 electrons around central atom must be in _____ or later

molecular orbital model

electrons in a molecular are delocalized over the whole molecule

resonance

more than one valid lewis structure possible

• actual structure in an average of all possible equivalent lewis structures

electrons

valid resonance structures involve movement of ____, not atoms

resonance

makes bond lengths, bond strength, and bond order the same

resonance

must have at least one double/triple bond to have:

formal charge

the number of valence electrons - the lone pari electrons on atom -1/2 the number of boding electrons

polyatomic ion

sum of a formal charge must equal charge for a:

lowest

best Lewis structure will have the ___ possible formal charge on each atom

electronegative

all negative formal charges will be on the most ___ element (almost always O)

VSEPR

valence shell electron pair repulsion

VSEPR

electron pairs need to be as far apart from one another as possible

more

lone pairs take up ____ space than bonding pairs

electron domain geometry

the arrangement of the electrons in space around an atom

molecular geometry

arrangement of the atoms in space around a central atom

AX2

linear shape, linear e domain

AX3

trigonal planar shape and e geometry

AX2E

bent shape, trigonal planar e geometry

AX4

tetrahedral shape and e geometry

AX3E

trigonal pyramidal shape and tetrahedral e geometry

AX2E2

bent shape, tetrahedral e geometry

AX5

trigonal bipyramidal shape and e geometry

AX4E

seesaw shape, trigonal bipyramidal e geometry

AX3E2

T shape, trigonal bipyramidal e geometry

AX2E3

linear shape, trigonal bipyramidal e domain

AX6

octahedral shape and e domain

AX5E

square pyramidal shape and octahedral e domain

AX4E2

square planar shape, octahedral e domain

AX4

any carbon compound with 4 single bonds

AX3E

any N or P compound with 3 single bonds

AX2E2

O and S compounds with 2 single bonds

AX5

p compounds

<120

bent

180

linear

120

trigonal planar

109.5

tetrahedral

107

trigonal pyramidal

104.5

bent (AX2E2)

90 and 120

trigonal bipyramidal

90 and 120

seesaw

90

T shape

90

octahedral

90

square pyramidal

90

square planar

hybridization

mixing of an atoms atomic orbital to form hybrid orbitals with identical energy

single bonds

sp3

triple bonds

sp

double bonds

sp2

sigma

single has one ___ bond

pi

triple has two ____ bonds and one sigma bond

one

double has ___ sigma and pi bond

tetrahedral

sp3

trigonal planar

sp2

linear

sp

lattice energy

increases as the ions charge increases

O

most electronegative atom