Question

Metal peroxides are ionic compounds containing (1) \(\mathrm{O}_{2}\) (2) \(\mathrm{O}^{2}\) (3) \(\mathrm{O}_{2}^{2-}\) (4) \(\mathrm{O}\)

Short answer

The correct answer is (3) \(\mathrm{O}_{2}^{2-}\).

Step-by-step solution

Identify the Correct Component

Determine which of the given options correctly represents the peroxide ion. A peroxide ion consists of two oxygen atoms bonded together and has a total charge of -2.

Compare Options

Compare each option with the correct structure of a peroxide ion: 1. \(\mathrm{O}_{2}\)2. \(\mathrm{O}^{2}\)3. \(\mathrm{O}_{2}^{2-}\)4. \(\mathrm{O}\)

Reason through Options

Consider the chemical structure and charge:1. \(\mathrm{O}_{2}\) - Just two oxygen atoms, not indicating any charge.2. \(\mathrm{O}^{2}\) - Suggests an incorrect oxidation state of oxygen.3. \(\mathrm{O}_{2}^{2-}\) - Correct: Two oxygens bonded together with a -2 charge.4. \(\mathrm{O}\) - Single oxygen atom.

Conclusion

Conclude that the correct representation of a peroxide ion is \(\mathrm{O}_{2}^{2-}\).

Key concepts

ionic compounds

Ionic compounds are formed when atoms transfer electrons between each other. This results in ions that stick together due to opposite charges. Metals typically lose electrons and form positive ions (cations). Non-metals usually gain these electrons and form negative ions (anions).

In metal peroxides, the metal part combines with the peroxide ion \(O_{2}^{2-}\). Sodium peroxide (Na\_{2}O\_{2}) is an example. Sodium (Na) loses one electron to become Na\^{+} ion, and peroxides \(\text{O}_2^{2-}\) pair with these metal cations.

peroxide structure

A peroxide ion consists of two oxygen atoms bonded together. This differs from a standard oxygen molecule (O\_{2}), where the two oxygen atoms don't carry an overall charge.

In peroxide, each oxygen in a \(O_{2}^{2-} \) ion has an oxidation state of -1. This is why the whole ion carries a -2 charge. The structure helps make the peroxide ion an important part of some chemical reactions, particularly those involving oxidation and reduction.

chemical charge

Chemical charge helps to balance chemical equations and understand the behavior of molecules. Peroxide ions carry a total charge of -2, which means each oxygen atom in the ion has a -1 charge.

This charge balance is critical in reactions. For example, in sodium peroxide (Na\_{2}O\_{2}), we use two Na\^{+} ions to balance the \(O_{2}^{2-} \) ion's charge.

• A single Na\^{+} would be insufficient since its +1 charge wouldn't balance \(O_{2}^{2-} \)'s -2 charge.
• Always ensure the total positive and negative charges in a compound balance out to zero.

This understanding is fundamental when studying chemistry and predicting compound behavior.