1. Unit 2.1: Lewis Dot Structures and Ionic Bonding

2. Bell Work October 6 Bell Work:
Agenda:
Turn in Test Corrections and anything you forgot to turn in while I was gone
Planner: No Homework
Notes
Lewis Dot Structure Activity
Bell Work:
Write down 2 things you learned while I was on Outdoor Ed.
My Favorite Demonstration of All Time

3. Chemical Reactions When substances react and new substances form
Chemical Bond: the force of attraction that holds two atoms together as a result of the rearrangement of electrons between them.
When atoms bond, electrons may be transferred from one atom to another or shared between the atoms.
Chemical Reactions are shown with chemical equations
Chemical Reactions Video

4. Chemical Equations
Show the rearrangement of atoms to form new substances in a chemical reaction
Example:
CH4 + 2O2  CO2 + 2H2O
Reactants: The substances that react; what you start with (left side of arrow)
Products: The substances that are produced; what you make (right side of arrow)

5. Reading a Chemical Equation
CH4 + 2O2  CO2 + 2H2O
CH4: Methane
O2: Oxygen
CO2: Carbon Dioxide
H2O: Water
“Methane and oxygen react to form carbon dioxide and water”
+ : “and”
 : “react to form”
Coefficients are the number of molecules of each substance

6. Valence Electrons Electrons in the outermost shell of an atom
Atoms can give away, take away, or share electrons to get to 0 or 8 valence electrons
Remember, they want an empty or full valence shell, if they don’t have one then they are unstable (HAPPY OCTOPUS!)

8. Lewis Dot Structures of Elements
Lewis Dot structures are used to show valence electrons
Can be helpful when predicting how elements bond
Rules:
Look on the periodic table to determine how many valence electrons are in an element
Write the symbol of the element
Imagine that the element is in a box with 4 sides
Start on top and rotate clockwise putting one dot (electron) at a time
Continue to circle, double electrons when needed.
Do not add more than 2 electrons to each side

9. Write the Lewis Dot Structure for the following Elements:
Lithium (Li):
Aluminum (Al):
Bromine (Br):

10. Bell Work October 7 Bell Work:P
How many valence electrons do the following elements have? He Cl Ne H Li
Agenda:
Turn in Article and Article Summary
Planner: Lewis Dot Structure of Ionic Compounds
Lewis Dot Structure Activity
Notes

11. Ions An Ion is a charged particle
The number of electrons is NOT equal to the number of protons
Atoms become charged particles when they gain or lose electrons

12. Cations and Anions Cations: Gained one or more electrons
Lost one or more electrons
Negatively Charged
Positively Charged
Non-metals form anions
Metals form Cations
Anions:

13. Naming Ions Cations: Anions: Name of Atom + Ion Stem of atom + ide
Example:
Sodium becomes Sodium Ion
Fluorine become Fluoride
Calcium becomes Calcium Ion
Nitrogen becomes Nitride

14. What type of Ions do each group form?
Remember, elements are lazy, they do whatever is easiest
They want to either gain or lose electrons to get to 0 or 8 valence electrons
Example:
If I have 1-3 valence electrons, it is easier to lose electrons than to gain them
If I have 5-7 valence electrons, it is easier to gain electrons than to lose them
IF I have 4, I could go either way

16. Bell Work: Bell Work October 8
Label the following as a metal or a nonmetal. Label if it will form a cation or an anion. N Al F Li
Agenda:
Planner: Lewis Dot Structure of Ionic Compounds
Notes
Lewis Dot Structure of Ionic Compounds
Lattice Structure Activity

17. Ionic Charges Atom gaining electrons = anion
Adding a negatively charged particle makes the atom more negative
Atoms losing electrons = cation
Taking away an electron means you take away something that is negative. This makes the atom more positive
Example:
Negative people in your life will make you more negative
If you get rid of this negative person, then you will be happier or more positive

18. Ions form Ionic Bonds
Electrons are TRANSFERRED from one atom to another to form ions
This creates a negatively charged ion (anion) and a positively charged ion (cation)
Opposites attract, the anion is attracted to the cation, this creates an IONIC BOND
Dogs Teach Bonding Video

19. Ions form Ionic Bonds Transfer of electrons from metals to nonmetals
All Ionic Bonds are called “Salts”
Ionic Bonds are weak, compared to other types of bonds
Bond between METAL and NONMETAL

20. Lewis Dot Structures of Ionic Compounds
Na + Cl
K + F
Be + I + I

21. Properties of Ionic Bonds
Solubility: the ability to dissolve in a solvent (typically water, but can include other liquids such as alcohols)
Conductivity: describes if a substance can carry electric current
Melting Points: temperature at which compounds melt (Celsius)

22. Crystal Lattice Styrofoam Ball Activity
Positive ions (cations) are attracted to negative ions (anions)

23. Solubility Solubility: Ability to dissolve in a solvent
Insoluble: Not Soluble (Does not dissolve)
Partially Soluble: Only partially dissolves
Ionic compounds tend to dissolve well in water or alcohol but not in things like oil

24. Solubility
When ionic compounds dissolve, they are pulled out of their lattice structure and into their ionic state
Dissociation: when ionic compounds are pulled into their ions and out of their lattice structure
Ionic Dissociation Animation

25. Conductivity Conductivity: The ability to conduct electricity
Ionic compounds are not conductive in their solid state
They are conductive in their liquid state because the ions are dissociated
Aqueous: Dissolved in water
Electrolyte an aqueous salt solution
Conductivity Animation

26. Melting Point Melting Point (MP): temperature at which compounds melt
Melting Points are extremely high for ionic compounds due to their lattice structure and the strength of their bond

27. Flame Test
Metals turn a very specific color when exposed to flame if they are in an ionic compound
Every metal has it’s own specific color
You can identify an unknown metal by the color of the flame
They use this for fireworks!