Metallic
Substance
type
Metal element
Examples
Na, Fe, Cu
Structure
Giant lattice of
positive ions in a
‘sea’ of electrons
Bonding
Attraction of
delocalised
electrons for
positive ions binds
structure together
by strong metallic
bonds.
Properties
Melting and
boiling points
High m.pt.
Covalent
Network
Non-metals in
Group 3 and 4
or its
compound
Ionic
Covalent Molecular
Usually
metal/non-metal
compound(a
compound with
a relatively large
difference in
electronegativity
NaCl, CaO,
K2SO4
Non-metal elements or
usually non-metal/nonmetal compound
Diamond,
graphite, SiC,
B
Giant lattice of Giant lattice of
covalently
positive ions
bonded atoms and negative
ions
Atoms are
Attraction of
linked
positive ions for
throughout the negative ions
whole
gives strong
structure by
ionic bond.
strong
covalent
bonds.
Very high
m.pt.
High m.pt.
I2(s), S8(s), C8H18(l),
HCl(g), P4(s)
Discrete molecules
Strong covalent bonds
hold atoms together
within the separate
molecules held
together by weak
intermolecular forces
(London dispersion
forces or hydrogen
bonds).
Low m.pt. and b.pt.
(hydrogen bonding
raises m.pt. and b.pt.
compared with London
dispersion forces)
Solids, liquids or gases
State at room
temp.
Usually solid
Solid
Electrical
conductivity
Good conductors
Nonwhen solid or liquid conductors
(graphite is an
exception)
Solubility
Insoluble in polar
and non-polar
solvents
Solid
Non-conductors
when solid,
good conductors
when molten or
in aqueous
solution –
electrolytes.
Insoluble in all Soluble in polar
solvents
solvents,
insoluble in
non-polar
solvents
Non-conductors in all
states (a few e.g.
HCl(g) react with
water to form
electrolytes).
Generally insoluble in
polar solvents but
soluble in non-polar
solvents.