lattice energy of potassium fluoride is higher than potassium iodide explain
Answers
Answer:
The two main factors affecting lattice energy are the charges on the ions and the distance between the ions.
In magnesium chloride, 2+ ions are attracting 1- ions. In potassium iodide, the attraction is between 1+ and 1- ions.
Thus, the lattice energy of
KI
should be less than that of
MgCl
2
.
In
NaBr
, the attraction is between 1+ and 1- ions.
In
KI
,
K
+
is a bigger ion than
Na
+
and
I
-
is a bigger ion than
Br
-
.
The distance between ions is greater in
KI
, so
KI
should have a lower lattice energy and a lower melting point than
NaBr
.
A simple extrapolation from
NaCl
through
NaBr
suggests that
KI
should have a lattice energy of about 680 kJ/mol and a melting point of about 700 °C.
The actual values are 698 kJ/mol and 681 °C.