Ionic Compounds

Core Concept

Ionic compounds are composed of a cation and anion. The cation is typically a metal, and the anion is usually a nonmetal or a polyatomic ion (a group of atoms with an overall charge). If the compound contains a metal it is a good sign that it can be considered an ionic compound. 

  • Memorize Common Ions: Focus on learning the common polyatomic ions, charges, and patterns.

  • Roman Numerals for Transition Metals: Practice associating transition metals with their possible charges.

  • Cross-Method for Formulas: To determine the correct formula, use the “criss-cross” method to balance charges between cations and anions.

Test Yourself

Assorted Multiple Choice
A constant current is passed through an electrolytic cell for 45.0 minutes, delivering a total charge of 8,100 Coulombs. How many moles of electrons were transferred during this process? (Faraday's constant = 96,485 C/mol e⁻)

Podcast Episode

Episode

Ionic Nomenclature

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Student Guide Teacher Guide

Practice Problems & Worked Out Examples 🔒

Browse by category

01

Naming Binary Ionic Compounds (Fixed-Charge Metals)

→ 02

Writing Formulas for Binary Ionic Compounds (Fixed-Charge Metals)

→ 03

Naming Ionic Compounds with Transition Metals (Variable Charge)

→ 04

Writing Formulas for Ionic Compounds with Transition Metals (Variable Charge)

→ 05

Naming Ionic Compounds with Polyatomic Ions

→ 06

Writing Formulas for Ionic Compounds with Polyatomic Ions

→ 07

Determining Ion Charges and Interpreting Formulas

→ 08

Error Identification and Correction in Nomenclature

→ 09

Mixed Nomenclature

→ 10

Other / Uncategorized

→ 11

Assorted Multiple Choice

→

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Types of Ionic Compounds

  • Type I: Ionic compounds where the metal forms only one type of cation.

  • Type II: Ionic compounds where the metal can form multiple types of cations (transition metals with variable charges).

  • Type III: Compounds containing polyatomic ions.

WRITING FORMULA of Ionic Compounds

  1. Write the symbols and charges for each cation and anion. (Cation is written first.)

  2. Crisscross ONLY THE NUMBER (not +/-) OF THE CHARGE to the other ion - written as a subscript. (You may need to use parentheses if the cation or anion contains more than 1 element or has a subscript already written.)

  3. Simplify the numbers that were crisscrossed (now written as subscripts). (If the subscript is reduced to “1” then it should not be written and parentheses are not needed.)

Writing Names for Ionic Compounds

Video Resources

A screenshot of a handwritten chemistry diagram titled 'Lithium Oxide' showing the chemical reaction with lithium (Li), oxygen (O), and lithium oxide (Li2O), with color-coded elements and symbols for plus, minus, and arrows.
A woman with long dark hair wearing a white blazer, sitting in front of an orange background, looking directly at the camera with her hands clenched into fists.
Handwritten chemistry notes on a blackboard or paper, listing chemical symbols and their corresponding words: ClO4 minus - perchlorate, ClO3 minus - chlorate, ClO2 minus - chlorite, ClO minus - hypochlorite, Cl minus - chloride.