To determine the ions that can behave as oxidizing agents, we need to understand the concept of oxidation states and the role of oxidizing agents:
- Oxidizing agents are species that can accept electrons, thereby getting reduced themselves while oxidizing another species.
- In general, a higher oxidation state of an element is more likely to accept electrons, making it a potential oxidizing agent.
Now, let's analyze the given ions:
- \(\text{Sn}^{4+}\): Tin in the +4 oxidation state. It can potentially accept electrons to reduce to \(\text{Sn}^{2+}\), hence can act as an oxidizing agent.
- \(\text{Sn}^{2+}\): Tin in the +2 oxidation state. It is already in a lower oxidation state and more likely to act as a reducing agent instead by losing electrons.
- \(\text{Pb}^{2+}\): Lead in the +2 oxidation state. Similar to \(\text{Sn}^{2+}\), it is more likely to lose electrons and act as a reducing agent.
- \(\text{Tl}^{3+}\): Thallium in the +3 oxidation state. It can gain electrons to reduce to \(\text{Tl}^+\), serving as an oxidizing agent.
- \(\text{Pb}^{4+}\): Lead in the +4 oxidation state. It can accept electrons to reduce to \(\text{Pb}^{2+}\), thus can act as an oxidizing agent.
- \(\text{Tl}^{+}\): Thallium in the +1 oxidation state. It is in a lower oxidation state and more likely to lose electrons, acting as a reducing agent.
Based on the above analysis, the ions that can act as oxidizing agents are:
- \(\text{Sn}^{4+}\)
- \(\text{Pb}^{4+}\)
Thus, the number of ions expected to behave as oxidizing agents is 2.
Therefore, the correct answer is 2.