The activity series is a list of metals and their half-reactions
arranged in order of decreasing ease of oxidation or increasing
ability to take an electron. How do you use this series? Very
simply, any substance on the right-hand side of the arrows will
be strong enough to take an electron from any substance above it
on the left-hand side of the arrows. For example, if a Ag+
cation gets close to an Fe atom then the Ag+ cation will take an
electron away from the Fe atom. In terms of a chemical reaction
the activity series predicts 2Ag+ + Fe → 2 Ag + Fe2+ In
contrast, when a Fe2+ cation meets a Ag atom, the Fe2+ cation
will not be strong enough to take electrons away from the Ag
atom. That is, 2 Ag + Fe2+ —X→ 2Ag+ + Fe What happens when we
mix Ca metal and HCl acid? Ca(s) + HCl(aq) → ? First, we write
the complete ionic equation for the reactants. Ca(s) + H+(aq) +
Cl-(aq) → Then we ask if H+(aq) is strong enough to take an
electron away from Ca(s)? We look at the activity series and see
that H+ is below Ca so