Chapter 8 Homework
8A:
8.1- A) What are valence electrons? B) How many valence electrons does a
nitrogen atom possess? C) An atom has the electron configuration 1s2 2s2 2p6
3s2 3p2. How many valence electrons does the atom have?
8.2- A) What is the octet rule? B) How many electrons must a sulfur atom gain to
achieve an octet in its valence shell? C) If an atom has the electron configuration
1s2 2s2 2p5 how many electrons must it gain to achieve an octet?
8.4- What is the Lewis symbol for each of the following atoms or ions: A) Li, B)
Se, C) Al3+ D) S2-
8.5- Using Lewis symbols diagram the reaction between magnesium and oxygen
atoms to give the ionic substance MgO.
8.12- A) The lattice energies of NaF and MgO are given in table 8.2(Pg.265).
Account for the difference in these two quantities. B) Account for the difference
in the lattice energies of MgCl2 and SrCl2, which are also listed in the table.
8.21- A) Why are monoatomic cations smaller than their corresponding neutral
ions? B) Why are monoatomic anions larger than their corresponding neutral
atoms? C) Why does the size of ions increase as one proceeds down the periodic
table?
8.24- Select the ions or atoms from the following sets that are isoelectronic with
each other: a) K+, Rb+, Ca2+ B) Cu+, Ca2+, Sc3+, C) S2-, Se2-, Ar, D) Fe2+, Co3+, Mn2+
8.28- For each of the following sets of atoms and ions arrange the members in
order of increasing size: A) Se2-, Te2-, Se B) Co3+, Fe2+, Fe3+, C) Ca, Ti4+, Sc3+, D)
Be2+, Na+, Ne.
8B
8.32- Using Lewis Symbols and Lewis structures diagram the formation of SiCl4
from Si and Cl atoms.
8.47- Draw Lewis structures for the following: A) SiH4 B) CO C) SF2 D) H2SO4 (H
is bonded to O) E) ClO2- F) NH2OH (N and O are bonded to one another)
8.48- Write Lewis structures for the following: A) PCl3 B) O22- C) NO2+ D) PO33E) H2CO3 (both H atoms are bonded to C) F) C2H2 (the C atoms are bonded to one
another)
8.50- For each of the following molecules or ions of sulfur and oxygen, write a
single Lewis structure that obeys the octet rule, and calculate the formal charges
on all of the atoms: A) SO2 B) SO3 C) SO32- D) SO42-
8.54- Based on Lewis structures, predict the odering of N-O bond lengths in NO+
NO2-, and NO3-
8 C:
8.51- Draw the resonance structures that obey the octet rule for the following:
A) N2O (a nitrogen atom is the central atom) B) CO32- C) HCO2- (H and both O
atoms are bonded to the C)
8.52- Draw the resonance structures for the following: A) HNO3 (H is bonded to
O) B) NO2- C) N2O4 (each N atom is bonded to two O atoms and to the other N)
8.56- Mothballs are composed of naphthalene, C10H8, the structure of which
consists of two six-membered rings of carbon that are fused along an edge, as
shown in the following incomplete Lewis structure (turn to pg.297). A) write two
different complete Lewis structures for naphthalene B) The observed C-C bond
lengths in the molecule are intermediate between C-C single and C=C double
bonds. Explain. C) Represent the resonance in naphthalene in a way analogous to
that used to represent it in benzene.