Chapter 2 - Molecules

Question 1

Valence bond theory

Answer 1

treats the formation of a molecule as arising from the bringing together of complete atoms which, when they interact, to a large extent retain their original character.

Question 2

Molecular orbital theory

Answer 2

allocates electrons to molecular orbitals formed by the overlap (interaction) of atomic orbitals.

Question 3

Van der Waals forces include

Answer 3

dispersion and dipole-dipole interactions.

Question 4

Van der Waals forces operate ________ molecules.

Answer 4

between

Question 5

Van der Waals radius

Answer 5

Half the distance of closest approach of two non-bonded atoms of the same element.

Question 6

Valence bond theory considers

Answer 6

the interactions between separate atoms as they are brought together to form molecules.

Question 7

Diamagnetic species

Answer 7

All electrons are spin-paired; a diamagnetic substance is repelled by a magnetic field.

Question 8

Paramagnetic species

Answer 8

Contains one ore more unpaired electrons; a paramagnetic substance is attracted by a magnetic field.

Question 9

The number of molecular orbitals that can be formed must equal

Answer 9

the number of atomic orbitals of the constituent atoms.

Question 10

Bond order

Answer 10

= 1/2 (bonding electrons - antibonding electrons)

Question 11

The lower the bond order, the _________ the internuclear separation.

Answer 11

larger

Question 12

A basis set of orbitals

Answer 12

is composed of those which are available for orbital interactions.

Question 13

Isoelectronic species

Answer 13

Two species are isoelectronic if they possess the same total number of electrons.

Question 14

Hypervalent species

Answer 14

Atoms that contain more than 8 valence electrons.

Question 15

1 Debye (D) =

Answer 15

= 3.336 x 10^-30 Cm

Question 16

Stereochemically active

Answer 16

If the presence of a lone pair of electrons influences the shape of the molecule or ion.

Question 17

Stereochemically inactive

Answer 17

If the presence of a lone pair of electrons does not influence the shape of the molecule or ion.

Question 18

Diasteriomers

Answer 18

Stereoisomers that are not mirror images of one another.

Question 19

Enantiomers

Answer 19

Stereoisomers that are mirror images of one another.

Question 20

An octahedral species EX2Y4 can possess ________ and ________ arrangements.

Answer 20

Cis, trans

Question 21

An octahedral species EX3Y3 can possess ________ and ________ arrangements.

Answer 21

Fac, mer