Chapter 10

Question 1

molecular geometry

Answer 1

the general shape of a molecule, as determined by the relative positions of the atomic nuclei

Question 2

Valence-Shell Electron Pair Repulsion (VSEPR) Model

Answer 2

the VSEPR model predicts the shapes of molecules and ions by assuming that the valence-shell electron pairs (bonding and non-bonding) are arranged about each atom so that electron pairs are kept as far away from one another as possible, thereby minimizing electron pair repulsion

Question 3

A common feature of both trigonal planar

and tetrahedral VSEPR geometries is that

Answer 3

each site is equivalent and so there is

only one possibility of locating lone pairs

Question 4

Because a lone pair tends to require more space than a bonding
pair, it tends to

Answer 4

reduce the bond angles.

Question 5

A trigonal bipyramidal geometry has two distinct sites:

Answer 5

axial and equatorial.

Question 6

Dipole Moment:

Answer 6

A quantitative measure of the degree of charge

separation in a molecule

Question 7

dipole moment of polar bonds

Answer 7

A polar bond is characterized by separation of electrical charge.
Polar molecules, therefore, have nonzero dipole moments.

Question 8

SI unit for the dipole moment is the

Answer 8

coulomb•meter, also known as the

Debye (D).

Question 9

Polarity and Boiling Point

Answer 9

The attractive forces due to the polarity increases the amount of energy required for
the liquid to boil.

Question 10

is VSEPR theory always right?

Answer 10

no lol

Question 11

what provides a more accurate means of determining molecular structures?

Answer 11

molecular orbital theory

Question 12

a covalent bond forms when …

Answer 12

• An orbital on one atom comes to occupy a portion of
the same region of space of an orbital on the other
atom. The two orbitals are said to overlap.
• The total number of electrons in both orbitals is no
more than two.
• The greater the orbital overlap, the stronger the bond.

Question 13

Valence-bond theory

Answer 13

gives us the first description of covalent bonding in

terms of atomic orbitals (a quantum mechanical method).

Question 14

Hybridization

Answer 14

Hybrid orbitals are formed when two or more atomic
orbitals on the same atom are mixed to form a new set of hybrid
orbitals.

Question 15

The number of hybrid orbitals is equal to the number of

Answer 15

pure

atomic orbitals used in the hybridization process

Question 16

Covalent bonds are formed by:

Answer 16

a. Overlap of hybrid orbitals with atomic orbitals.

b. Overlap of hybrid orbitals with other hybrid orbitals.

Question 17

How Do I Predict the Hybridization of the Central Atom

Answer 17

Count the number of lone pairs AND the number of atoms

bonded to the central atom

Question 18

Orbital Diagrams and Valence Bond Theory: Valence bond theory allows us to explain this in two steps:

Answer 18

promotion and hybridization

Question 19

What happens during multiple bonding?

Answer 19

When more than one orbital from each bonding atom overlaps, a multiple
bond is formed.

Question 20

σ bond (sigma)

Answer 20

has a cylindrical shape
about the bond axis.
It is formed either when two s orbitals
overlap or with directional orbitals (p or
hybrid), when they overlap along their
axis.

Question 21

π bond (pi)

Answer 21

has an electron distribution above and below the bond axis.
It is formed by the sideways overlap of two parallel p orbitals.
This overlap occurs when two parallel half-filled p orbitals are
available after σ bonds have formed.

Question 22

Bond Orders

Answer 22

A single bond is σ-bond
A double bond is a σ-bond plus a π-bond
A triple bond is a σ-bond plus two π-bonds

Question 23

molecular orbital theory does not

Answer 23

constrain
the electrons to being localized between pairs of atoms, but
allows the electrons to occupy orbitals that are spread over the
entire molecule

Question 24

molecular orbitals are

Answer 24

mathematical functions
that can be used to indicate the probability of finding an electron at
a given position.

Question 25

Also like an atomic orbital, a molecular orbital can only

accommodate a maximum of

Answer 25

two electrons, in which case they

must have opposite spin.

Question 26

Molecular orbital theory definition

Answer 26

Bonds are formed from the interaction of atomic orbitals to form
molecular orbitals

Question 27

As two atoms approach each other, the orbitals overlap and interfere either

Answer 27

constructively (addition) or destructively (subtraction).

Question 28

bonding orbital

Answer 28

addition of orbitals builds up electron density in overlap region

Question 29

antibonding orbital

Answer 29

subtraction of orbitals results in low electron density in the overlap region

Question 30

An antibonding molecular orbital has

Answer 30

higher energy and lower stability than the

atomic orbitals from which it was formed.

Question 31

A bonding molecular orbital has

Answer 31

lower
energy and greater stability than the atomic
orbitals from which it was formed.

Question 32

Bond order:

Answer 32

the number of bonds that exist between two atoms can be

calculated using the equation:

Question 33

A bond order of zero means

Answer 33

a bond is not formed!

Question 34

Delocalization

Answer 34

is central feature of molecular orbital theory where rather than the lone pair of electrons contained in localize bonds (as in the valence bond theory), electrons can exist in molecular orbitals that are spread over the entire molecule