Properties of Ionic Compounds
Ionic solids are hard, brittle, and conduct when dissolved or molten.
About this topic
Ionic compounds form giant lattices with strong electrostatic attractions, giving them high melting and boiling points, and making them hard but brittle: a shift of layers brings like charges together, and the crystal shatters. They conduct electricity when molten or dissolved, when ions are free to move, but not as solids. Many dissolve in water.
The lattice holds each ion surrounded by oppositely charged neighbours in all directions, so a lot of energy is needed to separate them. Sodium chloride melts at 801 degrees Celsius. In a solid, ions are locked in place and cannot carry charge; once the lattice is broken by melting or by water molecules surrounding the ions, they can move and carry current. Compounds with highly charged, small ions have the strongest lattices and are less soluble.
Test it by dissolving salt in water and connecting a bulb: it lights up, while pure water or sugar solution does not. Hit a salt crystal with a hammer and it breaks into pieces with flat faces. Ionic compounds are used in electrolytes, ceramics, fertilisers and food.
Misconceptions: ionic compounds conduct as solids, or are made of molecules. They are neither. Not all ionic compounds dissolve; calcium carbonate and silver chloride are insoluble. Also, brittle is not the same as soft.
Key ideas
- High melting points
- Soluble in water often
- Do not conduct as solids
Quick check
Use cases: where Properties of Ionic Compounds helps
- Homework: review the key idea behind Properties of Ionic Compounds before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Properties of Ionic Compounds without notes.
- Visual learning: play with the interactive lab to see how Properties of Ionic Compounds changes when you adjust its inputs.
- Teaching a friend: explain Properties of Ionic Compounds in your own words, then compare your version with the key ideas.
Chemistry explains medicine, food, cleaning products, fuels and building materials.
Frequently asked questions
What is Properties of Ionic Compounds?
Ionic solids are hard, brittle, and conduct when dissolved or molten.
What will I learn in Properties of Ionic Compounds?
High melting points. Soluble in water often. Do not conduct as solids.
Is Properties of Ionic Compounds part of Chemistry?
Yes. It is one of 150 Chemistry topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Properties of Ionic Compounds lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Properties of Ionic Compounds?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.