Activity Series of Metals
| Rank | Element | Symbol | Ion Formed | Reacts with Water? | Reacts with HCl? | Notes |
|---|---|---|---|---|---|---|
| 1 | Lithium | Li | Li⁺ | Yes (vigorous) | Yes | Most reactive metal; reacts vigorously with cold water |
| 2 | Potassium | K | K⁺ | Yes (vigorous) | Yes | Reacts violently with water; stored under mineral oil |
| 3 | Barium | Ba | Ba²⁺ | Yes | Yes | Alkaline earth metal; reacts readily with cold water |
| 4 | Calcium | Ca | Ca²⁺ | Yes | Yes | Reacts with cold water, though less vigorously than Group 1 metals |
| 5 | Sodium | Na | Na⁺ | Yes (vigorous) | Yes | Reacts vigorously with water; common in many salts |
| 6 | Magnesium | Mg | Mg²⁺ | Yes (slow/steam) | Yes | Reacts slowly with cold water; reacts readily with steam and acids |
| 7 | Aluminum | Al | Al³⁺ | No (oxide layer) | Yes | Protective Al₂O₃ layer prevents reaction with water; reacts with acids |
| 8 | Manganese | Mn | Mn²⁺ | No | Yes | Reacts with dilute acids; important in steel production |
| 9 | Zinc | Zn | Zn²⁺ | No | Yes | Commonly used in galvanization to protect iron |
| 10 | Chromium | Cr | Cr³⁺ | No | Yes | Forms a protective oxide layer; used in stainless steel |
| 11 | Iron | Fe | Fe²⁺ / Fe³⁺ | No | Yes | Reacts with dilute acids to form Fe²⁺; rusts in moist air |
| 12 | Cobalt | Co | Co²⁺ | No | Yes (slowly) | Reacts slowly with dilute acids |
| 13 | Nickel | Ni | Ni²⁺ | No | Yes (slowly) | Reacts slowly with dilute acids; used in coins and alloys |
| 14 | Tin | Sn | Sn²⁺ | No | Yes (slowly) | Reacts slowly with dilute acids; used in tin plating |
| 15 | Lead | Pb | Pb²⁺ | No | Yes (slowly) | Reacts slowly with dilute HCl; PbCl₂ is slightly soluble |
| 16 | Hydrogen | H₂ | H⁺ | — | — | Reference point: metals above H displace H₂ from acids; metals below do not |
| 17 | Antimony | Sb | Sb³⁺ | No | No | Does not react with dilute acids |
| 18 | Bismuth | Bi | Bi³⁺ | No | No | Least reactive of the pnictogens |
| 19 | Copper | Cu | Cu²⁺ | No | No | Requires oxidizing acids like HNO₃ or hot concentrated H₂SO₄ |
| 20 | Mercury | Hg | Hg²⁺ | No | No | Liquid at room temperature; dissolves in oxidizing acids |
| 21 | Silver | Ag | Ag⁺ | No | No | Dissolves in HNO₃ but not HCl; used in jewelry and electronics |
| 22 | Platinum | Pt | Pt²⁺ | No | No | Extremely unreactive; dissolves only in aqua regia |
| 23 | Gold | Au | Au³⁺ | No | No | Least reactive metal; dissolves only in aqua regia (HCl + HNO₃) |
The series ranks metals by oxidation tendency — top of the list loses electrons most readily. Ordering is qualitative; for metals close in reactivity (Co/Ni, Sn/Pb) different sources sometimes swap adjacent positions, and the right tiebreaker is the quantitative standard reduction potential. Concentration, surface oxide layers, and overpotential effects can also override the simple ranking in practice (aluminum is a textbook example — thermodynamically reactive, but its Al2O3 skin makes it kinetically inert toward water). Note that aqueous acid behavior assumes dilute, non-oxidizing acid; copper, silver, and the like dissolve readily in HNO3 or hot concentrated H2SO4.
Frequently Asked Questions
How do you use the activity series to predict if a reaction will occur?
Find the free metal and the cation in the table. If the free metal sits above the cation's parent metal, the displacement runs forward. Zinc (rank 9) sits above copper (rank 19), so Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s) proceeds — you'll see copper plate out and the blue color fade. The reverse (Cu into ZnSO4) does nothing because copper is below zinc. Same logic applies to acids using hydrogen as the cutoff: Mg attacks HCl, Cu doesn't.
Why is hydrogen included in the activity series even though it is not a metal?
Hydrogen marks the cutoff for the most common lab question: does this metal dissolve in dilute HCl or H2SO4? Metals above H+ on the list reduce protons to H2 gas and dissolve. Metals below H+ — copper, mercury, silver, platinum, gold — won't touch dilute non-oxidizing acid. To dissolve those, you need an acid whose anion is itself an oxidizer (HNO3, hot concentrated H2SO4) or aqua regia for the noble metals. Including H gives you a single reference point that handles both metal-on-metal and metal-on-acid cases.
What is the difference between the activity series and the electrochemical series?
Same physics, two formats. The activity series is the qualitative shorthand — useful when you just want a yes/no on whether a reaction proceeds. The electrochemical series gives the underlying E° values in volts, lets you compute cell potentials, and includes non-metal half-reactions (Cl2/Cl-, O2/H2O) that the activity series leaves out. The two follow the same order: a more negative E°(reduction) corresponds to a stronger reducing agent and a higher position in the activity series. Use the activity series for fast prediction, the standard potentials when you need numbers.