Skip to main content
Pearson+ LogoPearson+ Logo
Ch.6 Ionic and Molecular Compounds
Timberlake - Chemistry: An Introduction to General, Organic, and Biological Chemistry 13th Edition
Timberlake13th EditionChemistry: An Introduction to General, Organic, and Biological ChemistryISBN: 9780134421353Not the one you use?Change textbook
Chapter 6, Problem 111d

Consider an ion with the symbol X2+ formed from a representative element.
d. What is the formula of the compound formed from X and the nitride ion?

Verified step by step guidance
1
Identify the charge of the nitride ion. The nitride ion (N³⁻) has a charge of -3 because nitrogen gains three electrons to achieve a stable octet configuration.
Determine the charge of the X ion. The problem states that X has a charge of +2, represented as X²⁺.
Balance the charges to form a neutral compound. To achieve charge neutrality, the total positive charge from X²⁺ ions must equal the total negative charge from N³⁻ ions. This requires finding the smallest whole-number ratio of X²⁺ to N³⁻ that balances the charges.
Write the formula of the compound. To balance the charges, you will need 3 X²⁺ ions (total charge = +6) and 2 N³⁻ ions (total charge = -6). Combine these in the ratio of 3:2 to form the neutral compound.
Express the formula of the compound. The formula is written as X₃N₂, where the subscripts indicate the ratio of X ions to N ions in the compound.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
49s
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Ionic Compounds

Ionic compounds are formed when atoms transfer electrons, resulting in the formation of positively charged cations and negatively charged anions. The electrostatic attraction between these oppositely charged ions leads to the creation of a stable compound. Understanding the charges of the ions involved is crucial for determining the correct formula of the compound.
Recommended video:
Guided course
02:11
Naming Ionic Compounds

Nitride Ion

The nitride ion is a negatively charged ion (N³⁻) formed when nitrogen gains three electrons. It is important to recognize the charge of the nitride ion when combining it with cations, as this will influence the stoichiometry of the resulting ionic compound. The nitride ion typically forms stable compounds with various metals and metalloids.
Recommended video:
Guided course
01:09
Ions and the Octet Rule Example 3

Charge Balance

Charge balance is a fundamental principle in forming ionic compounds, where the total positive charge from cations must equal the total negative charge from anions. For the compound formed from the cation X²⁺ and the nitride ion N³⁻, the charges must be balanced to determine the correct ratio of ions in the formula. This ensures the compound is electrically neutral.
Recommended video:
Guided course
03:12
Balancing Redox Reactions (Simplified) Example 2