Topic 4: Intermolecular forces and metallic bonding

Question 1

Structure, giant covalent

Answer 1

Very hard but brittle. Very high melting point and boiling point. Do not
conduct in any state. Insoluble.

Question 2

Structure, giant ionic

Answer 2

Hard but brittle. High melting point and boiling point. Conduct when molten or
aqueous, but not as solids.

Question 3

Structure, giant metallic

Answer 3

Malleable, not brittle. Melting point and boiling point dependent on no. of
valence e-. Good conductivity.

Question 4

Structure, molecular covalent

Answer 4

Usually soft and malleable unless hydrogen bonded.
Low melting point and boiling point. Do not conduct in any state. Often soluble in non-aqueous solvents,
unless they can hydrogen bond to water.

Question 5

Allotropes

Answer 5

Occur when an element can exist in different crystalline forms, such as in
carbon, which can exist as graphite, fullerene and diamond.

Question 6

Bond polarity

Answer 6

A polarity caused by a difference in electronegativity between the
elements. The greater the difference, the greater the polarity.

Question 7

Covalent bond

Answer 7

Bonding by the sharing of electrons. The electrons are shared and
attracted by both nuclei resulting in a directional bond between the two atoms.

Question 8

Dative bond

Answer 8

A bond in which both electrons come from one of the atoms. Also
known as coordinate bond.

Question 9

Ionic bond

Answer 9

A bond by which electrons are transferred from one atom to another to
form ions with complete outer shells.

Question 10

Conductivity

Answer 10

The extent to which a substance can conduct electricity. Must possess
electrons or ions that are free to move.

Question 11

Delocalization

Answer 11

The sharing of one electron pair by more than two atoms.

Question 12

Forces, dipole-dipole

Answer 12

Permanent electrostatic forces of attraction between polar
molecules. Stronger than van der Waals’.

Question 13

Forces, Hydrogen bonding

Answer 13

Occurs when hydrogen attached to a highly
electronegative element (N, F, or O) is bonded to another highly electronegative
element (N, F, or O). Stronger than dipole:dipole forces.

Question 14

Forces, van der Waal’s

Answer 14

Temporary dipole forces due to momentary unevenness in
spread of electrons. Weakest of intermolecular forces. Increase with increasing molar
mass.

Question 15

Hybridization

Answer 15

The mixing of atomic orbitals to create new orbitals of the same
energy.

Question 16

Metallic bonding

Answer 16

The valence electrons in metals become detached from the
individual atoms so that the metals consist of a closely packed lattice of + ions in a
‘sea’ of delocalized electrons. Forces of attraction are between ions and electrons and
not between the ions themselves, which means that metals are malleable and ductile.

Question 17

Molecular polarity

Answer 17

Depends on both the bond polarity and the symmetry.
Resonance hybrid: Structures that arise from the possibility to draw a multiple bond in
different positions equivalently. Can be better explained by delocalization.

Question 18

Solubility

Answer 18

The extent to which one substance dissolves in another.
VSEPR theory: Valence Shell Electron Pair Repulsion theory. States that pairs of
electrons arrange themselves around the central atom so that they are as far apart from
each other as possible. Greater repulsion between lone pair of electrons than bonded
pairs.