4.8 The Activity Series of the Elements
- used to determine whether a reaction occurs
between a given ion and a given element
depending on the relative ease with which
the various species gain or lose electrons
(i.e., the relative ease with which the species
are reduced or oxidized)
Activity series - ranks elements in order of
their reducing ability in aqueous solution
The Activity Series of the Elements
Reducing and oxidizing abilities and the Periodic Table
More reactive
metal
Less reactive
metal
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Important things to note in Table 4.3 (Activity Series)
i.)
elements at the top of the table give up e- readily
and are stronger reducing agents
These are metals in group 1A & 2A; are powerful
reducing agents and even react with water
ii.)
metals in middle of series - react with aqueous acid
but not with water
iii.)
elements at the bottom give up e- less readily
and are very weak reducing agent
- do not react with aqueous acid or water
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Activity Series
NOTE: any element higher in the activity series will
reduce the ion of any element lower in the activity
series
M (s) + Yn+ (aq)
Mn+ (aq) + Y (s)
Position of H2 in activity series is particularly important because it
indicates which metals react with aqueous acid (H+) to release H2
gas
Activity series looks at the relative reactivity of a free metal
with an aqueous cation.
Fe(s) + Cu2+(aq)
Zn(s) + Cu2+(aq)
Fe2+(aq) + Cu(s)
Zn2+(aq) + Cu(s)
Cu(s) + 2 Ag+(aq)
2 Ag(s) + Cu2+(aq)
Mg(s) + 2 H+(aq)
Mg2+(aq) + H2(g)
Problem: Given the following three reactions, determine the
activity series for Cu, Zn, & Fe.
Fe(s) + Cu2+(aq)
Fe2+(aq) + Cu(s)
Zn(s) + Cu2+(aq)
Zn2+(aq) + Cu(s)
Fe(s) + Zn2+(aq)
NR
Problem: Using the activity series, write balanced chemical
equations (and net ionic) for the following reactions . If no
reaction occurs write down NR
(a) Al(s) + ZnCl2(aq)
(b) Ni (s) + MnBr2 (aq)
(c ) Zn (s) + HF (aq)
(d) Pt(s) + HBr(aq)
(e) Ca (s) + H2O (l)
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