Reactivity Series of Metals

The reactivity series is a list of metals arranged in order of their reactivity from highest to lowest. It is also known as the activity series. Metals at the top are highly reactive, while those at the bottom are least reactive.

Factors Affecting Reactivity:

a. Electron Configuration: Metals lose electrons to form positively charged ions.

b. Atomic Size: Metals with larger atomic size have loosely held outer electrons, making them more reactive.

c. Position in the Series

• Highly reactive metals (K, Na, Ca, Mg, Al) react with water and acids.
• Moderately reactive metals (Zn, Fe, Pb, Cu) react with acids but not with water.
• Less reactive metals (Ag, Au, Pt) do not react under normal conditions.

Reactivity series of metals

Salient Features of the Reactivity Series:

1. Electropositivity Decreases Down the Series

• Metals at the top are more electropositive.
• Potassium is the strongest reducing agent.

2. Reaction with Acids: Metals above hydrogen in the series can displace hydrogen from acids.

3. Displacement Reactions: A more reactive metal displaces a less reactive metal from its salt solution.

Example: Fe + CuSO₄ → FeSO₄ + Cu

4. Metal Extraction

• Highly reactive metals are extracted by electrolysis.
• Moderately reactive metals (Zn to Hg) are extracted by reducing their oxides.

5. Electron Donation Capacity Decreases Down the Series: Metals at the top donate electrons more readily than those at the bottom.

• Displacement reactions help compare metal reactivity better than reactions with water, oxygen, or acids.
• If one metal displaces another from its salt, it is more reactive (e.g., iron > copper).
• The reactivity series arranges metals from most to least reactive.
• Metals are grouped into highly, moderately, or less reactive categories.
• Metals lose electrons; nonmetals gain electrons to form ionic compounds like NaCl and MgCl₂.