IB Chemistry Topic R3.2 Electron Transfer Reactions…

Metals: The Ease of Oxidation

Metals are excellent reducing agents because they tend to lose electrons and form positive ions (cations) during chemical reactions.
But why do some metals lose electrons more readily than others?
This depends on their position in the periodic table and their intrinsic reactivity.
Group 1 Metals (Alkali Metals):
1. These metals are highly reactive because they have only one valence electron, which is easily lost.
2. Reactivity increases as you move down the group because the outermost electron is farther from the nucleus, experiencing weaker electrostatic attraction.
Other Metals:
1. For metals outside Group 1, their reactivity can be tested experimentally using displacement reactions.
2. A more reactive metal will displace a less reactive metal from its ionic solution.

Example

When zinc metal is placed in a solution of copper(II) sulfate $ \text{CuSO}_4 $, the following reaction takes place: $$\text{Zn}(s) + \text{Cu}^{2+}(aq) \rightarrow \text{Zn}^{2+}(aq) + \text{Cu}(s)$$
Here, zinc is oxidized to $ \text{Zn}^{2+} $ (it loses electrons), and copper(II) ions are reduced to copper metal (they gain electrons).
This demonstrates that zinc is more reactive than copper.

Metals are excellent reducing agents because they tend to lose electrons and form positive ions (cations) during chemical reactions.
But why do some metals lose electrons more readily than others?
This depends on their position in the periodic table and their intrinsic reactivity.
Group 1 Metals (Alkali Metals):
1. These metals are highly reactive because they have only one valence electron, which is easily lost.
2. Reactivity increases as you move down the group because the outermost electron is farther from the nucleus, experiencing weaker electrostatic attraction.
Other Metals:
1. For metals outside Group 1, their reactivity can be tested experimentally using displacement reactions.
2. A more reactive metal will displace a less reactive metal from its ionic solution.

Example

When zinc metal is placed in a solution of copper(II) sulfate $ \text{CuSO}_4 $, the following reaction takes place: $$\text{Zn}(s) + \text{Cu}^{2+}(aq) \rightarrow \text{Zn}^{2+}(aq) + \text{Cu}(s)$$
Here, zinc is oxidized to $ \text{Zn}^{2+} $ (it loses electrons), and copper(II) ions are reduced to copper metal (they gain electrons).
This demonstrates that zinc is more reactive than copper.