hw5 - petrosky(cep927 H05 Bonding 1 mccord(51600 This...

petrosky (cep927) – H05: Bonding 1 – mccord – (51600) 1
This print-out should have 25 questions.
Multiple-choice questions may continue on
the next column or page – find all choices
before answering.
001 10.0 points
Let X be a hypothetical element.
Which of the following would be largest?
1. X
2. X
2+
3. X
2 -
4. X
+
5. X
-
002 10.0 points
If the following crystallize in the same type of
structure, which has the lowest lattice energy?
1. BaS
2. SrO
3. CaO
4. SrS
5. BaO
003 10.0 points
Use the expression for the Coulomb potential
energy to calculate the energy for formation
of 1 mole of sodium chloride ion-pairs; i.e. , the
energy change for the reaction
Na
+
(g) + Cl
-
(g) → Na
+
Cl
-
(g)
Assume the distance between the ions in the
product is 283 pm.
Answer in units of kJ / mol.
004 10.0 points
What is the crystal lattice energy of LiI? Sub-
limation energy for Li is 155 kJ/mol and ion-
ization energy for Li is 520 kJ/mol. Sublima-
tion energy for I
2
is 62 kJ/mol and dissocia-
tion energy for I
2
is 151 kJ/mol. The electron
a ffi nity for I is - 295 kJ/mol. The heat of
formation for LiI(s) = - 271 kJ/mol.
1. - 215.5 kJ/mol
2. +726.5 kJ/mol
3. +215.5 kJ/mol
4. - 757.5 kJ/mol
005 10.0 points
In general, electronegativity tends to decrease
1. from bottom to top and from left to right
on the periodic table.
2. from top to bottom and from left to right
on the periodic table.