Question

Arrange the following metals in the order in which they displace each other from the solution of their salts. Al, Cu, Fe, Mg and Zn.

Short answer

Mg, Al, Zn, Fe, Cu.

Step-by-step solution

Understand the Reactivity Series

The reactivity series is a list of metals arranged in order of decreasing reactivity. Metals at the top of the series are more reactive and can displace metals below them from their salts. Familiarize yourself with the general reactivity order of common metals, including Al, Cu, Fe, Mg, and Zn.

Identify the Metals and Their General Placements

The metals presented are Aluminum (Al), Copper (Cu), Iron (Fe), Magnesium (Mg), and Zinc (Zn). Roughly, these metals align in the reactivity series as: Mg > Al > Zn > Fe > Cu. This order is determined based on their ability to lose electrons and form cations.

Order the Metals According to Reactivity

Using the general placements identified in Step 2, arrange the metals from the most reactive to least reactive: First, place Magnesium (Mg) as the most reactive, followed by Aluminum (Al), then Zinc (Zn), next Iron (Fe), and finally Copper (Cu) as the least reactive. This order reflects their capacity to displace another metal from its salt solution.

Key concepts

Metal Displacement

Metal displacement is a fundamental concept in chemistry that illustrates how more reactive metals can replace less reactive metals in their compounds. Understanding this idea helps us predict which reactions will occur when metals are mixed. This concept comes to life in what is known as a 'metal displacement reaction'.

In such reactions, a metal essentially pushes out or displaces another metal from a solution of its salt. For instance, if you have a solution of copper sulfate and add zinc metal to it, zinc will displace copper because zinc is more reactive. This means zinc takes the place of copper in the compound, forming zinc sulfate in the process. Similarly, copper gets precipitated out as a solid metal. This type of reaction is simple yet mighty in explaining chemical metal behavior, especially in industrial processes like metal extraction and recovery.

• More reactive metals will always displace less reactive metals in such solutions.
• These reactions are not just theoretical but practical, occurring in many laboratory and industrial scenarios.
• Understanding these reactions opens the door to mastering topics like corrosion and galvanization.

Reactivity Order

Reactivity order is the backbone of predicting metal displacement reactions. It is a list ranking metals from most to least reactive. By knowing this order, you can easily determine which metal can displace another.

For the metals given in the exercise, Magnesium (Mg) tops the charts as the most reactive. This is followed by Aluminum (Al), Zinc (Zn), Iron (Fe), and finally, Copper (Cu), which is the least reactive. This sequence, known as a reactivity series, is central to understanding why some metals corrode more easily and why others are excellent for use in coinage and jewelry.

• Reactivity is linked to a metal's tendency to lose electrons and form positive ions or cations.
• More reactive metals have a higher tendency to lose electrons compared to less reactive metals.
• The reactivity series guides decisions in metal extraction from ores and recycling processes.

Metal Cations

Metal cations are positively charged ions formed when metals lose electrons. This formation is a critical part of why metals can participate in displacement reactions. Metals such as those arranged in the reactivity series—Al, Cu, Fe, Mg, and Zn—transform into cations during such reactions.

To delve deeper, when a metal displaces another in a solution, it loses electrons to become a cation, usually represented as something like Zn²⁺ or Fe²⁺. The displaced metal gains these electrons and settles as a solid beneath. Cations help explain why different metals have varied uses in technology and industry—more reactive metals often form stable cations readily, influencing their applications in batteries, electrical conductors, and catalysis.

• Forming cations is why metals have applications in electroplating and battery production.
• Some metal cations like those of copper are vital in biological systems and enzymatic processes.
• Recognizing the formation and role of cations aids in environmental discussions on pollution and heavy metal contamination.