, Energy
aka lattice
Lattice chapter a
enthalpy
surrounds
F =
To +
system A
&E =
Tot
lattice energy (AHiatt) an ionic compound is formed from its gaseous ions
:
energy change when I mole of
standard conditions
↓
energy given out when ions of opp charges come together
↑ exothermic (bonding together of ions ,
not separation)
↳ large exothermic value shows ionic lattice v stable w respect to gaseous ions
↓ the Hiatt the the ionic bonding in the lattice
more exothermic , stronger
* cannot determine Atlant by direct experiment
AHiatt
+
.
e . Na (g)
g + (1- (g) >
-
NaCI (s) = -787kJ MOl .
# of atomisation (AH) :
standard enthalpy change when I mole of gaseous atoms is formed
from its element under standard conditions
↓ endothermic :
energy is supplied to break the bonds holding the atoms in the element together
e .
g
. (i (s) eLi
(g) 1 Hato =
+ 161k) Mol .
-
z((z(g) =
((g)
electron affinity (EA)
EA ,
Alt when 1 mole of es is added to 1 mole of gaseous atoms to form / mole of gaseous ions with
a
single neg charge under SC
.
.
EA2 2-ions formed
Due to repulsion of
↓ net change exothermic
·
neg
ions + es (requires
energy)
EA ,
exothermic => Az endothermic (and EAz)
RHS elements have ? EA be gain e-to become Stable
*
8 (g) 02 (9) EAz 798k)
-
+ e - = + .
Mol
FA 348k) MOl
-
0 0
=
-
(g)
-
e
+
(g)
.
,
-141 + 198
Overall AH in forming oxide ion : add EA ,
+ FAz :
+
= + 657kJ Mo .
,
,
aka lattice
Lattice chapter a
enthalpy
surrounds
F =
To +
system A
&E =
Tot
lattice energy (AHiatt) an ionic compound is formed from its gaseous ions
:
energy change when I mole of
standard conditions
↓
energy given out when ions of opp charges come together
↑ exothermic (bonding together of ions ,
not separation)
↳ large exothermic value shows ionic lattice v stable w respect to gaseous ions
↓ the Hiatt the the ionic bonding in the lattice
more exothermic , stronger
* cannot determine Atlant by direct experiment
AHiatt
+
.
e . Na (g)
g + (1- (g) >
-
NaCI (s) = -787kJ MOl .
# of atomisation (AH) :
standard enthalpy change when I mole of gaseous atoms is formed
from its element under standard conditions
↓ endothermic :
energy is supplied to break the bonds holding the atoms in the element together
e .
g
. (i (s) eLi
(g) 1 Hato =
+ 161k) Mol .
-
z((z(g) =
((g)
electron affinity (EA)
EA ,
Alt when 1 mole of es is added to 1 mole of gaseous atoms to form / mole of gaseous ions with
a
single neg charge under SC
.
.
EA2 2-ions formed
Due to repulsion of
↓ net change exothermic
·
neg
ions + es (requires
energy)
EA ,
exothermic => Az endothermic (and EAz)
RHS elements have ? EA be gain e-to become Stable
*
8 (g) 02 (9) EAz 798k)
-
+ e - = + .
Mol
FA 348k) MOl
-
0 0
=
-
(g)
-
e
+
(g)
.
,
-141 + 198
Overall AH in forming oxide ion : add EA ,
+ FAz :
+
= + 657kJ Mo .
,
,
