1. Ionic and Covalent bonding

2. Bonds All atoms are trying to get enough electrons so that their valence shell is full. All atoms are trying to get enough electrons so that their valence shell is full. This is referred to as the OCTET RULE or This is referred to as the OCTET RULE or Atoms of elements will lose, gain, or share electrons in such a way that their electron configurations contain eight valence electrons. Atoms of elements will lose, gain, or share electrons in such a way that their electron configurations contain eight valence electrons. Elements can do this in several ways. Elements can do this in several ways.

3. Ionic bonds An ionic bond is the result of attraction between positive and negative ions. An ionic bond is the result of attraction between positive and negative ions. Ionic compounds come together in a way that balances out the charges on the ions. Ionic compounds come together in a way that balances out the charges on the ions. Scientists write compounds a specific way – by a chemical formula. Scientists write compounds a specific way – by a chemical formula. The ions are both represented by their atomic symbol, and the number of atoms of each is represented with a subscript number. The ions are both represented by their atomic symbol, and the number of atoms of each is represented with a subscript number.

4. For Example A ionic compound containing a magnesium ion with a charge of 2+ bonds with chlorine. A ionic compound containing a magnesium ion with a charge of 2+ bonds with chlorine. Chlorine has a 1- charge so 2 chlorine atoms are needed to balance out the 2+ charge. Chlorine has a 1- charge so 2 chlorine atoms are needed to balance out the 2+ charge. The chemical formula would be MgCl 2. The chemical formula would be MgCl 2.

5. Naming ionic compounds The name of the positive ion goes first followed by the name of the negative ion. The name of the positive ion goes first followed by the name of the negative ion. Of the negative ion is a single element then the end of its name changes to –ide. Of the negative ion is a single element then the end of its name changes to –ide. NaCl – sodium chloride NaCl – sodium chloride MgCl 2 – magnesium chloride MgCl 2 – magnesium chloride

6. If the ionic compound is polyatomic the name usually ends in –ate, or –ite If the ionic compound is polyatomic the name usually ends in –ate, or –ite NH 4 NO 3 - ammonium nitrate NH 4 NO 3 - ammonium nitrate

7. ….. See if you can figure out what the chemical formula for a compound containing Sodium (Na) and Chloride (Cl) would be. See if you can figure out what the chemical formula for a compound containing Sodium (Na) and Chloride (Cl) would be. How about a compound of Calcium (Ca) and Carbon (C ) and oxygen (O). How about a compound of Calcium (Ca) and Carbon (C ) and oxygen (O).

8. Check for understanding Write the chemical formulas for the following compounds. Write the chemical formulas for the following compounds. Sodium bromide Sodium bromide Lithium oxide Lithium oxide Magnesuim sulfide Magnesuim sulfide Aluminum fluoride Aluminum fluoride Potassium nitrate Potassium nitrate Ammonium chloride Ammonium chloride

9. Properties of ionic compounds Hard, brittle crystals that have high melting points. Hard, brittle crystals that have high melting points. When dissolved in water or melted they conduct electricity. When dissolved in water or melted they conduct electricity.

10. Covalent bonds