Chem 1020 Summer 2007
Quiz 2 Form A
Name: ___Answer key_______________________
1. Write the abbreviated electron configuration for Pb.
[Xe] 6s2 4f14 5d10 6p2
2. Write the full electron configuration for the Ca+ ion.
1s2 2s2 2p6 3s2 3p6 4s1 (Many of you just wrote neutral calcium’s configuration. The
Ca+ ion has one fewer electron.)
Is this a stable ion? Why or why not?
NO! Stable ions have a noble gas electron configuration. We would never see a Ca+
ion in a compound.
3. Draw the Lewis electron-dot structure for NOF. (Remember which one is the
central atom! Make sure the correct total number of valence electrons is shown.)
Total # ve = 5 + 6 + 7 = 18 ve (all of which must be accounted for in the structure!)
Even with the hint in the question, many of you put oxygen as the central atom.
Remember, the central atom is the first element in the formula (but not hydrogen).
This is a neutral molecule, so all atoms will make their normal number of bonds.
The central N has 3 bonds, O has two and F has one. So, if we put it together and
complete the octets, this is the structure:
O
N
F
4. Complete the following tables:
Name
Type (I, II, or III)
Ion pair
Formula
calcium nitride
I
Ca2+/N3–
Ca3N2
titanium (IV) sulfide
II
Ti4+/S2–
Ti2S4 → TiS2
Formula
Type (I, II, or III)
Ion pair
Name
Cu2O
II
Cu + /O2!
copper (I) oxide
N2Cl4
III
none
dinitrogen tetrachloride
Chem 1020 Summer 2007
Quiz 2 Form B
Name: _____Answer key_____________________
1. Write the abbreviated electron configuration for Bi.
[Xe] 6s2 4f14 5d10 6p3
2. Write the full electron configuration for the Ca2+ ion.
1s2 2s2 2p6 3s2 3p6 (Many of you just wrote neutral calcium’s configuration. The
Ca2+ ion has two fewer electrons.)
Is this a stable ion? Why or why not?
YES! Stable ions have noble-gas electron configurations (8 valence electrons). In
this case, the Ca2+ ion has argon’s electron configuration.
3. Draw the Lewis electron-dot structure for CNF. (Remember which one is the
central atom! Make sure the correct total number of valence electrons is shown.)
Total # ve = 4 + 5 + 7 = 16 ve (all of which must be accounted for in the structure!)
Even with the hint in the question, many of you put nitrogen as the central atom.
Remember, the central atom is the first element in the formula (but not hydrogen).
This is a neutral molecule, so all atoms will make their normal number of bonds.
The central C has 4 bonds, N has 3 and F has 1. So, if we put it together and
complete the octets, this is the structure:
N
C
F
4. Complete the following tables:
Name
Type (I, II, or III)
Ion pair
Formula
aluminum oxide
I
Al3+/O2–
Al2O3
chromium (VI) phosphide
II
Cr6+/P3–
Cr3P6 → CrP2
Formula
Type (I, II, or III)
Ion pair
Name
WS2
II
W 4+ / S2!
tungsten (IV) sulfide
P2O4
III
none
diphosphorus tetroxide