1. Chemical Reactions
Section 2.2

2. Learning Objectives
Explain how the number of valence electrons of an atom is related to its chemical properties
Explain the relationship between atoms, molecules, and compounds
Explain what has occurred when a reaction reaches dynamic equilibrium
Identify the reactants & products of a chemical reaction

3. Molecule Vs. Compound Molecule = two or more atoms joined together N2
Compound = Two or more elements make up the molecule H2 O3
H2O
NaCl

4. Chemical Reactions
Happen because atoms want an octet (8 electrons) in their valence shell
Chemical reactions create molecules & compounds
Nobel Gases  Are unreactive
Already have an octet in their valence shell

5. Chemical Reactions (Continued)
Described by chemical equations
Reactants = things you start out with in a reaction
Products = things that are created by the reaction
Coefficients = Numbers before reactants or products that tell the number of things in a reaction

7. Dynamic Equilibrium Reactions don’t stop!
They reach dynamic equilibrium
Dynamic equilibrium = the reaction is making products & reactants at the same rate
Shown by double arrows ↔ or