The metal cadmium tends to form Cd²⁺ ions. The following observations are made: (i) When a strip of zinc metal is placed in CdCl₂(aq), cadmium metal is deposited on the strip. (ii) When a strip of cadmium metal is placed in Ni(NO₃)(aq), nickel metal is deposited on the strip. (b) Which elements more closely define the position of cadmium in the activity series?

Key Concepts

Activity Series of Metals

The activity series is a list of metals ranked by their ability to displace other metals from solutions of their ions. More reactive metals, like zinc, can displace less reactive metals, such as cadmium, from their compounds. This series helps predict the outcomes of single displacement reactions and the relative reactivity of metals.

Redox Reactions

Redox (reduction-oxidation) reactions involve the transfer of electrons between substances, leading to changes in oxidation states. In the given observations, cadmium ions are reduced to cadmium metal, while zinc is oxidized, demonstrating the electron transfer that characterizes these reactions. Understanding redox processes is crucial for analyzing metal displacement.

Electrochemical Series

The electrochemical series is a list of standard electrode potentials for various half-reactions, indicating the tendency of a species to gain or lose electrons. Metals higher in the series are more likely to be oxidized, while those lower are more likely to be reduced. This concept is essential for determining the relative positions of cadmium, zinc, and nickel in the activity series.