1. Chemical Bonds (They’re everywhere!)

2. Back in their day…  Scientists used to taste the compounds they used or made in labs  One of these is salt, one is sugar…  How can two things that look so similar taste so different?

3. Chemical Bonds  Most of the matter around you is in bonds  Chemical bonds are combinations of two or more atoms  There are a few different types of bonds, each with unique properties

4. Bond Types  Ionic Bonds: Atoms are held together by bonds formed by attraction of oppositely charged ions  Example: Table Salt  Metallic Bonds: Form a crystal structure of metal cations with electrons flowing throughout  Example: Copper  Covalent Bonds: Atoms are held together by bonds formed by sharing electrons  Example: Water

5. Chemical Formulas – Ionic Compounds  Binary Ionic Compounds: Two atoms  One positively charged metal ion (ex. Na + )  Called a CATION  One negatively charged ion (ex. Cl - )  Called an ANION  Formula Unit: The simplest ratio of ions involved  NaCl  IONS have a charge, COMPOUNDS are neutral

6. Steps for Writing Ionic Formulas  Determine charge of ions (Group Number or Look up Polyatomic ion charges)  Al +3 O -2  Swap superscripts  So in each molecule there will be two aluminum ions and three oxygen ions

7. Naming Ionic Compounds  Name the cation then the anion (Cation is always first)  If the cation is a single atom (monatomic) just use the element name  Ex. KBrK = potassium  If the anion is a single atom, use the root of the element name plus the suffix -ide  Ex. KBr Br = Bromine  The root of Bromine is Brom, add –ide to get Bromide  Put the two together and you get potassium bromide

8. Practice with Your Neighbor  Everyone gets out a piece of paper  Pair up, the person on the left will choose cations  The person on the right will choose anions  Trade off writing the formula and naming ionic compounds  Put your name on the top, you will turn this in so I can see how we’re doing

9. Answer in your own words  What is a chemical bond?  Describe electrons in the three types introduced today.