Question

Write the chemical formula for each of the following, and indicate the oxidation state of the halogen or noble-gas atom in each: (a) xenon trioxide difluoride, \((\mathbf{b})\) chlorine dioxide, \((\mathbf{c})\) molybdenum hexafluoride, \((\mathbf{d})\) iodic acid, (e) sodium hypobromite, \((\mathbf{f})\) magnesium iodite.

Short answer

The chemical formulas and oxidation states for the given compounds are: a) Xenon trioxide difluoride: XeO₃F₂, oxidation state of Xe is +8. b) Chlorine dioxide: ClO₂, oxidation state of Cl is +4. c) Molybdenum hexafluoride: MoF₆, oxidation state of Mo is +6. d) Iodic acid: HIO₃, oxidation state of I is +5. e) Sodium hypobromite: NaBrO, oxidation state of Br is +1. f) Magnesium iodite: Mg(IO₂)₂, oxidation state of I is +3.

Step-by-step solution

a) Xenon trioxide difluoride

First, we need to identify the elements involved: xenon (Xe), oxygen (O), and fluorine (F). The prefixes 'tri' and 'di' tell us there are three oxygen atoms and two fluorine atoms. The chemical formula is XeO₃F₂. To find the oxidation state of Xe, we can set up an equation based on the oxidation state of oxygen (-2) and fluorine (-1), and then solve for Xe: \(x + 3(-2) + 2(-1) = 0 \Rightarrow x = +8\). The oxidation state of xenon in the compound is +8.

b) Chlorine dioxide

Chlorine (Cl) and oxygen (O) are the elements involved. In chlorine dioxide, there is one chlorine and two oxygen atoms. The chemical formula is ClO₂. The oxidation state of oxygen is -2, so to find the oxidation state of chlorine, we set up the equation: \(x + 2(-2) = 0 \Rightarrow x = +4\). The oxidation state of chlorine in the compound is +4.

c) Molybdenum hexafluoride

The elements in this compound are molybdenum (Mo) and fluorine (F). The prefix 'hexa' indicates that there are six fluorine atoms. The chemical formula is MoF₆. The oxidation state of fluorine is -1. To find the oxidation state of Mo, we set up an equation: \(x + 6(-1) = 0 \Rightarrow x = +6\). The oxidation state of molybdenum in the compound is +6.

d) Iodic acid

In iodic acid, the elements involved are iodine (I), hydrogen (H), and oxygen (O). The chemical formula is HIO₃. The oxidation state of hydrogen is +1 and for oxygen is -2. To find the oxidation state of iodine, we set up an equation: \((+1) + x + 3(-2) = 0 \Rightarrow x = +5\). The oxidation state of iodine in the compound is +5.

e) Sodium hypobromite

The elements in the sodium hypobromite are sodium (Na), bromine (Br), and oxygen (O). The chemical formula is NaBrO. The oxidation state of sodium is +1 and for oxygen is -2. To find the oxidation state of bromine, we set up an equation: \( (+1) + x + (-2) = 0 \Rightarrow x = +1\). The oxidation state of bromine in the compound is +1.

f) Magnesium iodite

Magnesium (Mg) and iodine (I) are the elements in magnesium iodite. This compound contains the iodite ion (IO₂⁻). The chemical formula is Mg(IO₂)₂. The magnesium ion (Mg²⁺) has an oxidation state of +2 and each iodite ion has a charge of -1. The oxidation state of iodine in the iodite ion is found by setting up an equation: \(x + 2(-2) = -1 \Rightarrow x = +3\). The oxidation state of iodine in the compound is +3.

Key concepts

Chemical Formula

A chemical formula represents the composition of molecules and compounds using symbols for the elements involved, alongside numerical subscripts to show the number of atoms of each element present in the compound. For instance, in the compound xenon trioxide difluoride ( XeO₃F₂ ), the chemical formula indicates that there is one xenon atom, three oxygen atoms, and two fluorine atoms.
Understanding chemical formulas enables scientists to predict the types of chemical reactions a compound can undergo, as well as the resulting products.
Some common types of compounds include oxides, consisting of oxygen and another element, and halides, which involve elements bonded with halogens like fluorine.

Halogen Compounds

Halogen compounds are chemical compounds that contain one or more halogens bonded to another element. Halogens, which are Group 17 elements like fluorine (F), chlorine (Cl), bromine (Br), and iodine (I), are known for their high reactivity.
For example, in the compound chlorine dioxide (ClO₂), chlorine is bonded to two oxygen atoms. It's important to note that halogens typically form bonds to achieve a stable electron configuration.

• Halogens often exhibit a typical oxidation state of -1 due to their tendency to gain one electron.
• They can also form compounds with varied oxidation states, as seen in compounds like ClO₂, where chlorine has an oxidation state of +4.

This diversity in bonding and oxidation states makes halogen compounds critical in a variety of chemical reactions and applications.

Noble-Gas Compounds

Noble-gas compounds contain rare instances where Noble gases (Group 18 elements such as xenon) form stable compounds. Generally, noble gases are characterized by their lack of reactivity due to having complete electron shells. Yet, in certain conditions, heavier noble gases, like xenon, can form stable compounds.
For instance, xenon can combine with fluorine and oxygen to form xenon trioxide difluoride (XeO₃F₂). Here, xenon defies its usual non-reactive nature to form bonds, reflecting an oxidation state of +8.
The formation of noble-gas compounds is fascinating as they challenge the traditional perception of these elements as completely inert.

• Xenon forms several compounds like XeF₂ and XeO₄, broadening the scope of chemistry.
• Studies of these compounds can provide insights into bond formation and molecular structure.

Noble-gas compounds exemplify unique chemical phenomena and expand our understanding of chemical bonding.

Oxidation Number Calculation

Calculating oxidation numbers is key to understanding the distribution of electrons in molecules and identifying the charges on atoms within a compound.
Oxidation numbers help in determining how electrons are shared in chemical bonds, which is crucial in predicting the chemical behavior and reactivity of compounds.
Here's how to calculate the oxidation state of an atom in a compound:

• Identify the known oxidation states of other elements in the compound (e.g., oxygen generally has an oxidation state of -2, and hydrogen is usually +1).
• Assign the unknown oxidation number to the element of interest (e.g., "x" for xenon in XeO₃F₂).
• Create an equation reflecting the sum of oxidation states, equal to the net charge of the compound (zero for neutral molecules).
• Solve the equation to determine the unknown oxidation number.

Using this method, one can deduce the oxidation state, ensuring a comprehensive grasp of chemical reactions and molecular interactions.