1. Bell Ringer Bell Ringer 1. What is Sodium’s atomic mass? 2. How many protons does sodium have? 3. How many neutrons does sodium have?

2. The BIG ideas 1. Chemistry is everywhere in the world around us. Most matter exists as combinations of elements that are joined together chemically. 2. In a chemical reaction, matter is not created or destroyed, only rearranged. 3. Elements come together in specific and predictable ways to form the chemical compounds of the world.

3. REVIEW: Fill in the blanks. 1.2.3. Si Boron Br

4. Molecules and Chemical Formulas 1. A molecule is a group of 2 or more atoms held together by chemical forces.

5. 2. A chemical formula uses symbols and subscripts to identify the number of atoms in a molecule. H2OH2O Chemical Formula Molecule Symbol Subscript O H H Molecules and Chemical Formulas A molecule is a group of 2 or more atoms held together by chemical forces.

6. 3. The subscript is a number written to the right and slightly below its chemical symbol. SYMBOL subscript C 6 H 12 O 6 CO 2 O 2 N 2

7. 4. The subscript shows how many atoms of an element are in a molecule. H2OH2O Subscript How many hydrogen atoms are there in this water molecule?

8. 5. A chemical symbol without a subscript means that there is only 1 atom of that element in the molecule. H2OH2O 1.How many Oxygen atoms are there in this water molecule? 2.How many atoms are there TOTAL in this molecule?

9. SCIENCE SCHOLAR CHECK H2O2H2O2 1.How many hydrogen atoms are there in this molecule? 2.How many Oxygen atoms are there in this molecule? 3.How many atoms are there TOTAL in this molecule? O O H H

10. Let’s Practice Chemical FormulaElementsNumber of Atoms in Molecule Carbon dioxide CO 2 Total =

11. Let’s Practice Chemical FormulaElementsNumber of Atoms in Molecule Carbon dioxide CO 2 Carbon Oxygen Carbon - 1 Oxygen - 2 Total = 3

12. Let’s Practice Chemical FormulaElementsNumber of Atoms in Molecule Carbon dioxide CO 2 Carbon Oxygen Carbon - 1 Oxygen - 2 Total = 3 Salt NaCl Total =

13. Let’s Practice Chemical FormulaElementsNumber of Atoms in Molecule Carbon dioxide CO 2 Carbon Oxygen Carbon - 1 Oxygen - 2 Total = 3 Salt NaCl Sodium Chlorine Sodium – 1 Chlorine - 1 Total = 2

14. Let’s Practice Chemical FormulaElementsNumber of Atoms in Molecule Carbon dioxide CO 2 Carbon Oxygen Carbon - 1 Oxygen - 2 Total = 3 Salt NaCl Sodium Chlorine Sodium – 1 Chlorine - 1 Total = 2 Nitrogen gas N 2 Total =

15. Let’s Practice Chemical FormulaElementsNumber of Atoms in Molecule Carbon dioxide CO 2 Carbon Oxygen Carbon - 1 Oxygen - 2 Total = 3 Salt NaCl Sodium Chlorine Sodium – 1 Chlorine - 1 Total = 2 Nitrogen gas N 2 Nitrogen Nitrogen - 2 Total = 2

16. Let’s Practice Chemical FormulaElementsNumber of Atoms in Molecule Carbon dioxide CO 2 Carbon Oxygen Carbon - 1 Oxygen - 2 Total = 3 Salt NaCl Sodium Chlorine Sodium – 1 Chlorine - 1 Total = 2 Nitrogen gas N 2 Nitrogen Nitrogen - 2 Total = 2 Iron oxide Fe 2 O 3 Total =

17. Let’s Practice Chemical FormulaElementsNumber of Atoms in Molecule Carbon dioxide CO 2 Carbon Oxygen Carbon - 1 Oxygen - 2 Total = 3 Salt NaCl Sodium Chlorine Sodium – 1 Chlorine - 1 Total = 2 Nitrogen gas N 2 Nitrogen Nitrogen - 2 Total = 2 Iron oxide Fe 2 O 3 Iron Oxygen Iron – 2 Oxygen - 3 Total = 5

18. Let’s Practice Chemical FormulaElementsNumber of Atoms in Molecule Carbon dioxide CO 2 Carbon Oxygen Carbon - 1 Oxygen - 2 Total = 3 Salt NaCl Sodium Chlorine Sodium – 1 Chlorine - 1 Total = 2 Nitrogen gas N 2 Nitrogen Nitrogen - 2 Total = 2 Iron oxide Fe 2 O 3 Iron Oxygen Iron – 2 Oxygen - 3 Total = 5 Sugar C 6 H 12 O 6 Total =

19. Let’s Practice Chemical FormulaElementsNumber of Atoms in Molecule Carbon dioxide CO 2 Carbon Oxygen Carbon - 1 Oxygen - 2 Total = 3 Salt NaCl Sodium Chlorine Sodium – 1 Chlorine - 1 Total = 2 Nitrogen gas N 2 Nitrogen Nitrogen - 2 Total = 2 Iron oxide Fe 2 O 3 Iron Oxygen Iron – 2 Oxygen - 3 Total = 5 Sugar C 6 H 12 O 6 Carbon Hydrogen Oxygen Carbon – 6 Hydrogen – 12 Oxygen - 6 Total = 24

20. 1.HCl 2.H 2 O 2 3.C 6 H 12 O 6 For each of the molecules to the left, answer the following questions: How many of each element? How many protons total? How many electrons total? *Use your periodic table*

21. CLOSING 1.What elements are in each of these molecules? 2.How many atoms of each element are there in the molecule? 3.How many atoms are there total in the molecule? DID WE MEET OUR DAILY OBJECTIVE? DID WE MEET OUR DAILY OBJECTIVE? Students will use models to understand molecules and chemical formulas. KCl NH 4 C 6 H 14