In the ionic compounds the oxidation number of an ion

is the same as the charge of the ion.

The correct answer is option 1. is the same as the charge of the ion.

Let us delve into the concept of oxidation numbers and how they relate to the charges of ions in ionic compounds.

Oxidation Numbers in Ionic Compounds

The oxidation number (or oxidation state) of an atom in a compound is a measure of the degree of oxidation (loss of electrons) or reduction (gain of electrons) of that atom. In ionic compounds, oxidation numbers are particularly straightforward because they correspond directly to the charges on the ions.

Relationship Between Oxidation Number and Ion Charge

In ionic compounds:

Cations (positively charged ions) have positive oxidation numbers equal to their charge.

Anions (negatively charged ions) have negative oxidation numbers equal to their charge.

Examples

Sodium Chloride (NaCl)

Sodium ion: \(Na^+\)

Charge: +1

Oxidation number: +1

Chloride ion: \(Cl^-\)

Charge: -1

Oxidation number: -1

Calcium Chloride (CaCl_2)

Calcium ion: \(Ca^{2+}\)

Charge: +2

Oxidation number: +2

Chloride ions: \(Cl^-\)

Charge: -1 (each chloride ion)

Oxidation number: -1 (each chloride ion)

Aluminum Oxide (Al_2O_3)

Aluminum ions: \(Al^{3+}\)

Charge: +3

Oxidation number: +3

Oxide ions: \(O^{2-}\)

Charge: -2 (each oxide ion)

Oxidation number: -2 (each oxide ion)

How Oxidation Numbers Help in Understanding Ionic Compounds

Oxidation numbers are essential for:

Balancing Chemical Equations: They help ensure that the total number of electrons lost in oxidation equals the total number of electrons gained in reduction.

Identifying Redox Reactions: They allow us to identify which elements are oxidized and which are reduced.

Predicting Compound Formation: By knowing the oxidation states of elements, we can predict the formulas of the compounds they form.

In summary, the oxidation number of an ion in an ionic compound is the same as the charge of the ion. This relationship simplifies the determination of oxidation states in such compounds and aids in understanding their chemical behavior.

Thus, the correct statement is: (1) The oxidation number of an ion is the same as the charge of the ion.