General Chemistry Principles, Patterns, and Applications, 2011

A N S W E R S
1. Ti 2+ , 3d 2 ; V 2+ , 3d 3 ; Cr 2+ , 3d 4 ; Mn 2+ , 3d 5 ; Fe 2+ , 3d 6 ; Co 2+ , 3d 7 ; Ni 2+ , 3d 8 ; Cu 2+ , 3d 9 ; Zn 2+ , 3d 10 . Because Z eff increases
from left to right, Ti 2+ and V 2+ will have the most negative reduction potentials (be most difficult to reduce).
2.
3. Hg 2+ > Fe 2+ > Zr 4+ > Fe 3+ > Pt 4+
23.2 A Brief Survey of Transition-Metal Chemistry
L E A R N I N G O B JE C T I V E
1. To use periodic trends to understand the chemistry of the transition metals.
We turn now to a brief survey of the chemistry of the transition metals, beginning with group 3. As we shall see, the
two heaviest members of each group usually exhibit substantial similarities in chemical behavior and are quite
different from the lightest member.
Groups 3, 4, and 5
Group 3 (Sc, Y, La, and Ac)
As shown in Table 23.4 "Some Properties of the Elements of Groups 3, 4, and 5", the observed trends in
the properties of the group 3 elements are similar to those of groups 1 and 2. Due to their ns 2 (n −
1)d 1 valence electron configurations, the chemistry of all four elements is dominated by the +3 oxidation
state formed by losing all three valence electrons. As expected based on periodic trends, these elements
are highly electropositive metals and powerful reductants, with La (and Ac) being the most reactive. In
keeping with their highly electropositive character, the group 3 metals react with water to produce the
metal hydroxide and hydrogen gas:
Equation 23.1
2M(s) + 6H 2 O(l) → 2M(OH) 3 (s) + 3H 2 (g)
Note the Pattern
The chemistry of the group 3 metals is almost exclusively that of the M 3+ ion; the elements are powerful
reductants.
Moreover, all dissolve readily in aqueous acid to produce hydrogen gas and a solution of the hydrated
metal ion: M 3+ (aq).
Table 23.4 Some Properties of the Elements of Groups 3, 4, and 5
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