IONIC BONDS Chapter 5, Section2 pp. 158-163

Ions and Ionic Bonds Ion-atom or group of atom that has an electric charge When an atom loses an electron it becomes… Positive When an atom gains an electron is becomes… Negative

Polyatomic Ion-ions that are made of more than one atom Ionic Bond- the attraction between two oppositely charges particles

What has happened to sodium to give it a positive charge? ION CHARGE SYMBOL/FORMULA Sodium 1+ Na+ Magnesium 2+ Mg2+ Chloride 1- Cl- Sulfate 2- SO42- What has happened to sodium to give it a positive charge? What has happened to chlorine to give it a negative charge? Which elements from the chart could from ionic bonds together?

Chemical Formulas and Names The combination of symbols that represent the ratio of elements in a compound MgCl2 CaCO3

Naming Positive ion comes first, then negative ion When the negative ion is a single element (like Cl-), the end of the name changes to –ide Chlorine  Chloride If the negative ion is polyatomic (like NO3-), the end of the name changes to –ate or –ite. Nitrate Figure out the chemical formulas for the following ionic compounds using the chart on page 159 Lithium oxide Potassium nitrate

**ions come together in a way that balances out the charges** Lithium Oxide Lithium = Li has 1 valence electrons  will lose 1 electron giving it a 1+ charge = Li+ Oxygen = O has 6 valence electrons  will gain 2 electrons giving it a 2- charge = 02- **ions come together in a way that balances out the charges** Li2O

Properties of Ionic Compounds Hard, brittle crystals High melting points Electrical conductivity as a liquid