1. Chemical Reactions Ions, Molecules and Compounds

2. Forming Compounds Noble gases are unlikely to take part in chemical reactions – WHY? Noble gases are unlikely to take part in chemical reactions – WHY? When atoms collide, electrons interact When atoms collide, electrons interact An atom may give up electrons = cation An atom may give up electrons = cation An atom may gain electrons = anion An atom may gain electrons = anion An atom may share electrons = one pair, two pair or more An atom may share electrons = one pair, two pair or more

3. Forming Compounds Ionic Compounds Ionic Compounds Composed of cations and anions Composed of cations and anions Attraction is called an ionic bond Attraction is called an ionic bond Metal joined with non-metal Metal joined with non-metal Na + joined with Cl - Na + joined with Cl -

4. Forming Compounds Molecular Compounds Molecular Compounds Composed of pairs of electrons being shared Composed of pairs of electrons being shared Attraction is called a covalent bond Attraction is called a covalent bond Two non-metals Two non-metals O 2- joined with O 2- O 2- joined with O 2-

5. Chemical Names and Formulas Key Points to Remember: Key Points to Remember: Metal + Non-metal = Ionic Bond Metal + Non-metal = Ionic Bond Non-metal + Non-metal = Covalent Bond Non-metal + Non-metal = Covalent Bond Ionic Bond = Ionic Compound Ionic Bond = Ionic Compound Covalent Bond = Molecular Compound Covalent Bond = Molecular Compound

6. Chemical Names and Formulas Names and Formulas for Binary Molecular Compounds Ends in “~ide” Prefix System Mono is used only for the second element Element that is more to the left is written first If prefix ends in “o” or “a” and is followed by an “o”, then the vowel on the prefix is dropped NumberPrefix 1mono 2di 3tri 4tetra 5penta 6hexa

7. Chemical Names and Formulas (p.161) Ionic Binary Compounds – only have two elements present Ionic Binary Compounds – only have two elements present Ends in “~ide” Ends in “~ide” Polyatomic Ions – have more then two elements present Polyatomic Ions – have more then two elements present NameChemical Formula ammonium ion NH 4 + hydroxide ion OH - carbonate CO 3 2- nitrate NO 3 - sulfate SO 4 2- hydrogen carbonate HCO 3 - hydrogen sulfate HSO 4 - phosphate PO 4 3-

8. Multivalent Ions An element that can form an ion in more than one way. Element(ous)(ic) Iron (Fe)+2+3 Lead (Pb)+2+4 Tin (Sn)+2+4 Mercury+1+2 Copper+1+2