Physical Science Unit 1 Chapter 5 Lesson 1

Start-Up Retrieve a packet from the table by the door. Put your name on top Read over the time table Look through the packet Bring your packet to class everyday Due the day of the test Objectives ◦ Read and write chemical formulas ◦ Determine how many atoms make up certain compounds or molecules

Chemical Formulas Chemists have complied a language using the elements of the periodic table of as their language Chemical symbol- a one or two letter abbreviation ◦ Use them to write formulas

Chemical Formula A combination of chemical symbols and numbers used to represent a compound or indicate the atoms present in a molecule ◦ Subscript- the number after the symbol  Tells how many atoms of an element are in each molecule

2Na+Cl 2  2NaCl What is says ◦ Two atoms of sodium will form a chemical bond with one molecule of chlorine to make two units of salt

Binary Compounds Made of only two elements Option 1 –metal and nonmetal ◦ First word is a metal ◦ The second is the root of the non-metal plus ide ◦ Example: NaCl = Sodium chloride Option 2- two non metals ◦ First word is the name of the element to the far left ◦ The second is atom name plus suffix ide and root and suffix indicating number of atoms ◦ Example: ◦ CO2 = Carbon Dioxide

Prefixes Mono1 atom Di2 atoms Tri3 atoms Tetra4 atoms Penta5 atom Hexa6 atoms