Which is the most reactive metal?
Potassium
Understanding Metal Reactivity
The reactivity of metals is their tendency to lose electrons and form positive ions. Metals that lose electrons easily are considered more reactive. We can compare the reactivity of different metals using the reactivity series.
The Reactivity Series
The reactivity series is a list of metals arranged in order of decreasing reactivity. Metals higher up in the series are more reactive than those lower down. They can displace metals lower in the series from their compounds.
Here is a portion of the reactivity series, including the metals from the options:
| Metal | Reactivity |
|---|---|
| Potassium (K) | Most Reactive (Highest) |
| Sodium (Na) | High Reactivity |
| Calcium (Ca) | Moderate Reactivity |
| Magnesium (Mg) | |
| Aluminium (Al) | |
| Zinc (Zn) | |
| Iron (Fe) | Lower Reactivity (Lower) |
| Lead (Pb) | |
| Copper (Cu) | Least Reactive (Lowest) |
Looking at the options given:
- Sodium (Na)
- Calcium (Ca)
- Iron (Fe)
- Potassium (K)
Let's find their positions in the reactivity series:
- Potassium (K) is very high in the series.
- Sodium (Na) is below Potassium, but still high.
- Calcium (Ca) is below Sodium.
- Iron (Fe) is much lower in the series, below Calcium, Zinc, etc.
Comparing the positions, Potassium is the highest among Sodium, Calcium, and Iron in the reactivity series.
Identifying the Most Reactive Metal
Since the reactivity of metals decreases as we move down the series, the metal highest in the series among the given options is the most reactive. From our comparison:
- Potassium is above Sodium.
- Sodium is above Calcium.
- Calcium is above Iron.
Therefore, Potassium is the most reactive metal among the choices provided.
Conclusion
Based on the reactivity series, Potassium (K) is the most reactive metal among Sodium (Na), Calcium (Ca), and Iron (Fe).
Revision Table: Comparing Reactivity
| Metal | Position in Reactivity Series (relative) | Reactivity Level |
|---|---|---|
| Potassium (K) | Highest | Very High |
| Sodium (Na) | High | High |
| Calcium (Ca) | Above Iron, Below Sodium | Moderate |
| Iron (Fe) | Lowest | Low |
Additional Information on Metal Reactivity
The reactivity of alkali metals (Group 1) and alkaline earth metals (Group 2) generally increases down the group. Potassium is an alkali metal located below Sodium in Group 1, making it more reactive than Sodium. Calcium is an alkaline earth metal in Group 2, and both Sodium and Potassium are generally more reactive than Calcium. Iron is a transition metal and is significantly less reactive than the alkali and alkaline earth metals listed.
Highly reactive metals like Potassium react vigorously with water, acids, and even air.
Important Questions from Chemical Reaction
Which of the following statement is/are true?
I. In physical change new substance is formed. substance is formed.
II. In chemical change no new substance is formed.
Which of the following cells involves similar chemical reactions?
The information not obtained from balanced chemical equation is
Oxygen cannot be obtained by which one of the following methods?
Which of the following compound is responsible for tarnishing of silver?
