CHEM 1212 EXAM 1
1. 1. Which of the following statements is TRUE?
A) A covalent bond is formed through the transfer of electrons from one atom
to another.
B) A pair of electrons involved in a covalent bond are sometimes referred to as
"lone pairs."
C) It is not possible for two atoms to share more than two electrons.
D) Single bonds are shorter than double bonds.
E) A covalent bond has a lower potential energy than the two separate atoms.
Answer E) A covalent bond has a lower potential energy than the two separate atoms.
2. 2. Place the following in order of decreasing magnitude of lattice energy.
NaF RbBr KCl
A) RbBr > NaF > KCl
B) NaF > KCl > RbBr
,C) KCl > NaF > RbBr
D) NaF > RbBr > KCl
E) RbBr > KCl > NaF
Answer B) NaF > KCl > RbBr
3. 3. Choose the compound below that should have the highest melting point
according to the ionic
bonding model.
A) AlN B) MgO C) NaF D) CaS E) RbI
Answer A) AlN
4. 4. Place the following elements in order of increasing electronegativity.
Sr N Na
A) Sr < Na < N
B) Na < N < Sr
C) Sr < N < Na
D) N < Sr < Na
,E) N < Na < Sr
Answer A) Sr < Na < N
5. 5. Choose the bond below that is least polar.
A) P-F B) C-Br C) C-F D) C-I E) C-Cl
Answer D) C-I
6. 6. Draw the best Lewis structure for the free radical, NO2. What is the formal
charge on the N?
A) 0 B) +1 C) -1 D) +2 E) -2
Answer B) +1
, 7. 7. How many of the following elements can form compounds with an expand-
ed octet?
Pb Kr Si B
A) 0 B) 1 C) 2 D) 3 E) 4
Answer D) 3
8. Use the bond energies provided to estimate H
°=?
C2H4+H2-->C2H6
Bond Bond Energy (kJ/mol)
C-C 347
C-H 414
C=C 611
Ca
C 837
H-H 436
A) -128 kJ B) +98 kJ C) +700 kJ D) -102 kJ E) -166 kJ
1. 1. Which of the following statements is TRUE?
A) A covalent bond is formed through the transfer of electrons from one atom
to another.
B) A pair of electrons involved in a covalent bond are sometimes referred to as
"lone pairs."
C) It is not possible for two atoms to share more than two electrons.
D) Single bonds are shorter than double bonds.
E) A covalent bond has a lower potential energy than the two separate atoms.
Answer E) A covalent bond has a lower potential energy than the two separate atoms.
2. 2. Place the following in order of decreasing magnitude of lattice energy.
NaF RbBr KCl
A) RbBr > NaF > KCl
B) NaF > KCl > RbBr
,C) KCl > NaF > RbBr
D) NaF > RbBr > KCl
E) RbBr > KCl > NaF
Answer B) NaF > KCl > RbBr
3. 3. Choose the compound below that should have the highest melting point
according to the ionic
bonding model.
A) AlN B) MgO C) NaF D) CaS E) RbI
Answer A) AlN
4. 4. Place the following elements in order of increasing electronegativity.
Sr N Na
A) Sr < Na < N
B) Na < N < Sr
C) Sr < N < Na
D) N < Sr < Na
,E) N < Na < Sr
Answer A) Sr < Na < N
5. 5. Choose the bond below that is least polar.
A) P-F B) C-Br C) C-F D) C-I E) C-Cl
Answer D) C-I
6. 6. Draw the best Lewis structure for the free radical, NO2. What is the formal
charge on the N?
A) 0 B) +1 C) -1 D) +2 E) -2
Answer B) +1
, 7. 7. How many of the following elements can form compounds with an expand-
ed octet?
Pb Kr Si B
A) 0 B) 1 C) 2 D) 3 E) 4
Answer D) 3
8. Use the bond energies provided to estimate H
°=?
C2H4+H2-->C2H6
Bond Bond Energy (kJ/mol)
C-C 347
C-H 414
C=C 611
Ca
C 837
H-H 436
A) -128 kJ B) +98 kJ C) +700 kJ D) -102 kJ E) -166 kJ
