Chem 1104 - 2018 Summer Problem Set #8
1. Explain why the second ionization energy of sodium(4560 kJ/mole) is significantly higher
than the second ionization energy of magnesium(1450 kJ/mole), even though the first ionization
energy of sodium is less than that of magnesium.
2. Using differences in electronegativity, predict if the bond formed between the following atoms
will be ionic, polar covalent, or nonpolar.
a) B, Br; b) Ba, Br; c) Rb, Br; d) C, S; e) C, O; f) Al, Cl; g) C, H; h) C, I; i) C, N; j) Ca, N
3. Assign formal charges to the atoms in the following structures. Which do you think of the two
is the most likely structure? Explain.
a) b)
4. Draw lewis structures, including formal charges for the following molecules or ions. When a
subscript is added to a symbol in a formula, the atoms denoted are directly and separately bonded
to the atom immediately following or immediately preceeding it in the formula.
a) BrO-; b) IO4-; c) O22-; d) NO+; e) AsO33-; f) H2Se; g) CCl2O; h) BrSSCl; i) O3SSSO32-;
j) SO2Cl2
5. Draw the resonance forms for the following molecules: a) N3- ; b)FNNN; c) ClCN; d) ClNO2
6. The following are examples of molecules or ions that do not obey the octet rule. The
molecules or ions contain a central atom with an expanded octet and only contain single bonds.
The total number of valence electrons each molecule or ion calculated must equal the number of
valence electrons indicated by covalent bonds and lone pairs. Draw the lewis structure for each
molecule or ion and using VSEPR theory predict the geometry. a) SiF62- ; b) SF4; c) PF5; d)
XeF4
7. Describe the hybridization of the sulfur atom in SF2, SF4, SF6, molecules.
8. The bond distance in the BrCl molecule is 214 pm and has a charge separation of
8.9010-21 C. Calculate the dipole moment of the molecule. 1.00 D = 3.3410-30 Cm. Calculate
the percent partial ionic character of the Br-Cl bond. The unit charge, e, is 1.6010-19 C.
9. How can you account for the fact that the dipole moment of SO2 is 1.63 D, but that of CO2 is
zero?
H
C
H
N N
..
..
H
C
H
N N
..
....
