Question

Name the following compounds and assign oxidation states to the halogens in them: (a) \(\mathrm{Fe}\left(\mathrm{ClO}_{3}\right)_{3}\), (b) \(\mathrm{HClO}_{2}\), (c) \(\mathrm{XeF}_{60}\) (d) \(\mathrm{BrF}_{5}\), (e) \(\mathrm{XeOF}_{4}\), (f) \(\mathrm{HIO}_{3}\),

Short answer

(a) Iron(III) Chlorate; Chlorine oxidation state: +5. (b) Chlorous Acid; Chlorine oxidation state: +3. (c) Xenon Hexafluoride; Xenon oxidation state: +6. (d) Bromine Pentafluoride; Bromine oxidation state: +5. (e) Xenon Oxytetrafluoride; Xenon oxidation state: +6. (f) Iodic Acid; Iodine oxidation state: +5.

Step-by-step solution

For naming the compounds:

Follow the rules for naming ionic and covalent compounds. For ionic compounds, the name of the positive ion or radical stays the same, followed by the name of the negative ion or radical. For covalent compounds, we add Greek prefixes for the number of respective atoms, plus the name of the first element and the second element with the suffix -ide.

Finding the oxidation numbers of the halogens:

Apply the rules for determining oxidation numbers. The oxidation number of the halogens will depend on the specific compounds they are part of. Now let's apply these steps to the given compounds:

(a) \(\mathrm{Fe}\left(\mathrm{ClO}_{3}\right)_{3}\)

This is an ionic compound, where Fe is the metal (iron) and \(_3( \mathrm{ClO} _3)\) is the nonmetal polyatomic ion (chlorate). So, the name is Iron(III) Chlorate. To find the oxidation state of chlorine, use the rule that the sum of oxidation numbers should equal the overall charge on the compound. For \(\mathrm{ClO}_3^-\), the oxidation number of an oxygen is -2, so we have \(x + 3(-2) = -1\), thus the oxidation state of the chlorine is +5.

(b) \(\mathrm{HClO}_{2}\)

This is a covalent compound with only one chlorine atom, so we need not add any prefixes. The name is Chlorous Acid. The oxidation states for H and O in \(\mathrm{HClO}_{2}\) is +1 and -2, respectively. So we have \(1 + x + 2(-2) = 0\), which means the oxidation state for the chlorine is +3.

(c) \(\mathrm{XeF}_{6}\)

This is a covalent compound, so we use Greek prefixes to name it. Thus, the name is Xenon Hexafluoride. Since the sum of the charges in the compound should be equal to the overall charge, we have \(x + 6(-1) = 0\), which means the oxidation state of the xenon is +6.

(d) \(\mathrm{BrF}_{5}\)

This is a covalent compound as well, and its name is Bromine Pentafluoride. For this compound, we get \(x + 5(-1) = 0\), so the oxidation state of the bromine is +5.

(e) \(\mathrm{XeOF}_{4}\)

This is a covalent compound, named Xenon Oxytetrafluoride. Here, the oxidation numbers of O and F are -2 and -1, respectively. So, for this compound, we have \(x + (-2) + 4(-1) = 0\), which means the oxidation state of the xenon is +6.

(f) \(\mathrm{HIO}_{3}\)

This covalent compound's name is Iodic Acid. The oxidation states for H and O in \(\mathrm{HIO}_{3}\) is +1 and -2, respectively. So we have \(1 + x + 3(-2) = 0\), which means the oxidation state for the iodine is +5.

Key concepts

Naming Chemical Compounds

When it comes to naming chemical compounds, understanding the distinction between different types of compounds is crucial. Chemical compounds fall into two main categories: ionic and covalent. Each type has its own set of rules which must be followed to correctly name them.

• Ionic compounds consist of metals and non-metals. These are usually named with the cation (positive ion) first, followed by the anion (negative ion). For example, \( \mathrm{Fe}\left(\mathrm{ClO}_{3}\right)_{3} \) is named Iron(III) Chlorate, where Iron is the cation and chlorate is the anion.


• Covalent compounds occur between two non-metals. These are usually named using Greek prefixes like mono-, di-, tri- etc., to indicate the number of atoms involved. For instance, \( \mathrm{XeF}_{6} \) is named Xenon Hexafluoride, emphasizing the presence of six fluorine atoms.

Regardless of the type, the suffix "-ide" is typically added to the name of the second element in covalent compounds.

Ionic and Covalent Compounds

In chemistry, ionic and covalent compounds differ fundamentally in their composition and how they form:Ionic Compounds: These are formed when metals transfer electrons to non-metals resulting in positive and negative ions that attract each other. As seen with \( \mathrm{Fe}\left(\mathrm{ClO}_{3}\right)_{3} \), Iron (a metal) bonds with chlorate (a polyatomic non-metal).Covalent Compounds: These occur when two non-metals share electrons equally or unequally. Compounds like \( \mathrm{BrF}_{5} \) and \( \mathrm{HClO}_{2} \) are composed of non-metals sharing electrons to reach a stable configuration.

• Ionic compounds typically have higher melting and boiling points and conduct electricity when dissolved in water.


• Covalent compounds often have lower melting and boiling points and do not conduct electricity.

Chemical Nomenclature

Chemical nomenclature is the systematic approach for giving names to chemical compounds. This is key in communicating chemical information accurately and efficiently.

• For ionic compounds, the name consists of the metal followed by the non-metal. The non-metal's name changes to end in '-ide', or keeps its polyatomic ion name. For instance, \( \mathrm{BrF}_{5} \) maintains the name Bromine Pentafluoride to indicate its specific molecular composition.


• The Greek prefixes (like mono-, di-, tri-) used in covalent compound naming help indicate the precise number of each type of atom present in the compound. For example, "hexa-" as in \( \mathrm{XeF}_{6} \) signifies the presence of six fluorine atoms.

By assigning a standardized name, chemists ensure that everyone understands a compound to have the same structure and composition globally.