Electrochemical Series — Diagram and Applications — Notes

Image reference: Daniell Cell — classic electrochemical cell demonstrating electrode potential, EMF (1.1 V), and SHE reference framework for the electrochemical series

Electrode Reaction	E° (V)	Character
$Li^{+}$ + $e^{-}$ → Li	−3.04	Strongest reducing agent (top of activity series)
$K^{+}$ + $e^{-}$ → K	−2.93	Very strong reducing agent
$Na^{+}$ + $e^{-}$ → Na	−2.71	Strong reducing agent
$Al^{3+}$ + 3 $e^{-}$ → Al	−1.66	Moderate reducing agent
$Zn^{2+}$ + 2 $e^{-}$ → Zn	−0.76	Moderate reducing agent
$Fe^{2+}$ + 2 $e^{-}$ → Fe	−0.44	Weak reducing agent
2 $H^{+}$ + 2 $e^{-}$ → $H_{2}$	0.00	Reference (SHE)
$Cu^{2+}$ + 2 $e^{-}$ → Cu	+0.34	Weak oxidizing agent
$Ag^{+}$ + $e^{-}$ → Ag	+0.80	Moderate oxidizing agent
$Au^{3+}$ + 3 $e^{-}$ → Au	+1.50	Strong oxidizing agent
$F_{2}$ + 2 $e^{-}$ → 2 $F^{-}$	+2.87	Strongest oxidizing agent (bottom)

Top (most negative E°): Strongest reducing agents (easily oxidized, lose $e^{-}$ )
Bottom (most positive E°): Strongest oxidizing agents (easily reduced, gain $e^{-}$ )
Left of SHE (negative E°): React with dilute acids, liberate $H_{2}$
Right of SHE (positive E°): Noble/unreactive metals

Feasibility: A reaction A + $B^{2+}$ → $A^{2+}$ + B is spontaneous ONLY if E°( $A^{2+}$ /A) < E°( $B^{2+}$ /B), i.e., A is above B in the series.
Displacement: Metal higher in the series (more negative E°) displaces metal lower (more positive E°) from its salt solution.
E°cell: Always positive for spontaneous cells → upper element reacts with lower element's ion.