I am working on my chemistry homework Right now we are working on BornHaber lattice energy etc I am trying to

Question

I am working on my chemistry homework. Right now we are working on Born-Haber, lattice energy, etc. I am trying to

figure out question #65. I am confused on how to even begin.

iIg
Og) + e -0(g)
-141
o (g) + e–+ 02-(g)
878
Magnesium oxide exists as Mg2+02- and not as Mg+o-.
Explain.
-64. Compare the electron affinity of fluorine to the ionization
energy of sodium. Is the process of an electron being quot;pulledquot;
from the sodium atom to the fluorine atom exothermic or endo-
thermic? Why is NaF a stable compound? Is the overall forma-
tion of NaF endothermic or exothermic? How can this be?
65. Consider the following: Li(s) + 2 12(g) -gt; Lil(s) AH =
292 kJ. Lil(s) has a lattice energy of -753 KJ/mol. The ion-
ization energy of Li(g) is 520. KJ/mol, the bond energy of I2(g)
is 151 kJ/mol, and the electron affinity of I(g) is -295 KJ/mol.
Use these data to determine the heat of sublimation of Li(s).
66. Use the following data (in kJ/mol) to estimate AH for the reac-
tion S-(g) + e- -gt; S2-(g). Include an estimate of uncertainty.
Lattice
lonization
AHsub
AH?
Energy
Energy of M
of M
Na2S
-365
-2203
495
109
K,S
-381
-2052
419
90
Rb, S
-361
-1949
409
82
Cs2S
-360
-1850
382
78
S(s)
-gt;S(g)
AH = 277 kJ/mol
a-()
Science