1. Chemistry, Part 4: Molecules & Bonding
Science
with
Mr. Comans

2. In This Powerpoint:
The Importance of Molecules What is a molecule? How do molecules impact everyday life? What molecules should you know?

3. In This Powerpoint:
Molecule Models What is a molecular formula? What are subscripts? What are coefficients?

4. In This Powerpoint:
Bonds How do molecules form? What kinds of bonds should you know about? What is an ionic bond? What is a covalent bond?

5. The Importance of Molecules
Electrically neutral group of atoms held together by chemical bonds

6. Molecules You Should Know
Water
Diatomic Oxygen (the oxygen we breathe)
Triatomic Oxygen (ozone) H O H O O O O O

7. Molecules You Should Know
Glucose (Sugar)
Carbon Dioxide
Sodium Chloride H H H H O H O O H C C C C C C H O O H O H H H H O C O Na Cl

8. Molecules You Should Know
Diatomic Nitrogen
Diatomic Hydrogen
Methane N N H H H C H H H

9. Molecular Formulas
A molecular formula is a representation of a molecule using chemical symbols and subscripts.
A subscript is a small number after a chemical symbol that represents the number of atoms in each molecule.

10. Molecular Formulas Water H2O Carbon Dioxide CO2 Subscript
If there is no subscript after a symbol, there is only 1 atom of that element in each molecule.

11. Practice! See if you can guess what elements make up each molecule, plus how many atoms of each, based on the formula. O2
CaOH
CH4
C7H5N3O6
H2CO3
H2SO4
Oxygen – 2 atoms
Calcium – 1, Oxygen – 1, Hydrogen – 1
Carbon – 1, Hydrogen – 4
Carbon – 7, Hydrogen – 5, Nitrogen – 3, Oxygen 6
Hydrogen – 2, Carbon – 1, Oxygen – 3
Hydrogen – 2, Sulfur – 1, Oxygen - 4

12. Molecular Formulas
A coefficient is a number placed in front of a molecular formula to indicate how many molecules are present.
H2O
Currently:
2 atoms of Hydrogen
1 atom of Oxygen

13. This bad boy multiples everything in the formula!
Molecular Formulas
A coefficient is a number placed in front of a molecular formula to indicate how many molecules are present.
2H2O
Currently:
4 atoms of Hydrogen
2 atoms of Oxygen
This bad boy multiples everything in the formula!

14. Molecular Formulas
A coefficient is a number placed in front of a molecular formula to indicate how many molecules are present.
3H2O
Currently:
6 atoms of Hydrogen
3 atoms of Oxygen

15. Molecular Formulas
A coefficient is a number placed in front of a molecular formula to indicate how many molecules are present.
12H2O
Currently:
24 atoms of Hydrogen
12 atoms of Oxygen

16. H H O Bonds How are these molecules held together?
Why do they form in the first place?
Recall: H H O

17. H H O Bonds How are these molecules held together?
Why do they form in the first place? H H O

18. Bonds How are these molecules held together?
Why do they form in the first place?