Consider the compound, $TiO_2$. What is the charge of an oxide ion?
A. +2
B. -2
C. +4
D. -4
Answer (2)
The compound T i O 2 is neutral, so the sum of the charges is zero.
Titanium commonly has a +4 charge.
Setting up the equation: + 4 + 2 y = 0 , where y is the charge of the oxide ion.
Solving for y , we find the charge of the oxide ion to be − 2 .
Explanation
Problem Analysis We are asked to determine the charge of an oxide ion in the compound T i O 2 .
Understanding Neutrality The compound T i O 2 is neutral, meaning the sum of the charges of all ions in the compound must be zero. Titanium (Ti) and oxygen (O) form an ionic compound.
Setting up the Equation Let's denote the charge of Titanium as x and the charge of Oxygen as y . Since there is one Titanium ion and two Oxygen ions in the compound, we can write the equation: x + 2 y = 0
Considering Titanium's Charge Titanium (Ti) can have multiple oxidation states, but +4 is the most common and stable. Let's assume the charge of Titanium is +4. Then, we have: + 4 + 2 y = 0
Solving for Oxygen's Charge Solving for y , we get: 2 y = − 4 y = − 2
Final Answer Therefore, the charge of the oxide ion is -2.
Examples
Understanding the charge of ions is crucial in various real-life applications. For instance, in designing batteries, knowing the charges of ions like Lithium (Li+) and Oxide (O2-) helps in predicting the voltage and capacity of the battery. Similarly, in materials science, understanding ionic charges aids in creating new compounds with specific electrical and structural properties. In environmental science, the charges of ions are important in understanding the behavior of pollutants in water and soil.
The charge of the oxide ion in the compound T i O 2 is -2. This is determined by recognizing that the compound is neutral and setting up a charge equation based on the common oxidation state of titanium. Therefore, the correct answer is B. -2.
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