Middle School Physical Science: Chemical Bonding - Ionic Bonds — Flashcards

Ionic bonding is a type of chemical bonding that involves the electrostatic attraction between oppositely charged ions, or between two atoms with sharply different electronegativities, and is the primary interaction occurring in ionic compounds.
The crystal structure of ionic compounds is strong and rigid. It takes a lot of energy to break all those strong ionic bonds. As a result, ionic compounds are solids with high melting and boiling points.

For example, the melting point of sodium chloride is 801 °C and the boiling point is 1413 °C. Contrast these figures with the melting and boiling points of water, which is not an ionic compound. Water melts at 0 °C and boils at 100 °C. The rigid crystals of ionic compounds are also brittle and more likely to break than bend when struck. As a result, ionic crystals tend to shatter easily.    
Solid ionic compounds are poor conductors of electricity. The strong bonds between ions lock them into place in the crystal. However, ionic compounds are good conductors of electricity when they are in the liquid state or when they are dissolved in water. Most ionic compounds dissolve easily in water. When they dissolve, they separate into individual ions, which can move freely and carry electric current. Dissolved ionic compounds are called electrolytes.