1. MEETS
Bohr and Lewis
Covalent & Ionic

2. Other Atoms Why Do Ions Form
WE ALREADY KNOW ITS TO “FILL” THEIR VALENCE!
Atoms will gain or lose electrons in order to fill or empty their valence depending on which is easier.
BUT WHERE DO THESE ELECTRONS COME FROM OR GO
Other Atoms

3. Bonding Types: Covalent Bonds: Recall – Non-metals form negative ions
This means they “want” to gain electrons to stabilize
How can two atoms both gain electrons at the same time? THEY SHARE
Covalent Bonds:
Formed between two or more non-metals
Electrons are shared between atoms

4. BUT if a Metal were to meet a Non-Metal at the bar ?
When two atoms get close together, their valence electrons interact.
Ok so what if two metals walk into a bar? Well there would be a bar fight between the metals!
Metals “need” to get rid of electrons and there would be no way for them to strike a mutual deal
BUT if a Metal were to meet a Non-Metal at the bar ?

5. It would be love at first sight
It would be love at first sight. Well not quite, but they would be able to make each other happy since one “wants” to gain and the other “wants” to lose electrons
Ionic Bonds:
Formed between metals & non-metals
Electrons are transferred between atoms

6. No but seriously the analogy can help
Covalent Molecules – are attached and sharing electrons – this is like marriage. It is a strong connection that is difficult to break.  low reactivity
Ionic Compounds – are attracted to each other – this is like dating. The bond is “electric” but if another comes along you might move on. Ionic bonds are not as strong  high reactivity

7. Pause – Lets Take a Brain Break
Complete Part 1 of the Worksheet

8. Lewis Diagrams: Like simplified Bohr diagrams
Only valence electrons are shown
Dots representing electrons are placed around the element symbols (on 4 sides, imagine a box around the symbol)
Electron dots are placed singularly, until the fifth electron is reached, then they are paired.
Example: Nitrogen atom

9. Lewis Diagrams:
Note: the Lewis diagrams are the same (except for the symbols) for elements in the same family because they have the same number of valence electrons

10. Lewis Diagrams for Ions:
For positive ions: one electron dot is removed from the valence shell for each positive charge of the ion.
For negative ions: one electron dot is added to each valence shell for each negative charge of the ion.
Square brackets and the charge are placed around each ion
Example: Nitrogen ion

11. Lewis Diagrams For Ionic Bonds:
Let’s Try – Sodium and Chlorine
Lewis Diagrams For Ionic Bonds:
1) Draw each of their Lewis Diagrams
2) Show the transfer of electrons and then the resulting Ions and their charges

12. Lewis Diagrams For Ionic Bonds:
Now Let’s Try Magnesium and Oxygen
Draw each of their Lewis Diagrams
The Ionic Compound

13. Lewis Diagrams For Ionic Bonds:
Now Let’s Try Calcium and Chlorine
Draw each of their Lewis Diagrams
The Ionic Compound ?

14. Lewis Diagrams For Covalent Bonds:
valence electrons are drawn to show sharing of electrons.
Remember: All atoms “like” to have a full valence shell
The shared pairs (“bonding pairs”) of electrons are usually drawn as a straight line
“lone pairs” are the electrons not shared

17. Extension:
IntRAmolecular Forces
In the bonds
What holds a molecule together
IntERmolecular Forces
Attraction between one molecule and its neighboring molecules
What keeps matter in solid and liquid phases
Have you ever wondered why some elements and molecules are solid at room temperature, but others are liquids or gasses?

18. WHAT IS HAPPENING ATOMICALLY
IONIC
COVALENT
METAL (+) AND NON-METAL (-)
Positive and negative ions ATTRACT to one another
WEAK intramolecular Forces *
Tend to be very reactive
Recall the “just dating” analogy – these ions are attracted to each other, but if another ion come a long they are likely to form a bond with it = chemical reaction has occurred
Two or more NON-METALS (no ions form)
Bond of ATTACHMENT where electrons are shared
STRONG intramolecular Forces *
Tend to be very unreactive
Recall that these are the “married” couple. It take a lot of energy to divorce and meet a new spouse so chemical reactions are less likely

19. BOHR MODELS IONIC COVALENT Not very useful and not often used
Arrows show transfer of ions and then brackets show resulting charged ions that are attracted to each other
Useful for determine the shape, arrangement and bod types in the molecules
Lone pairs  bonds. For most elements, you are looking to satisfy the OCTET RULE  total of 8 shared electrons per atom
Ex. Carbon Dioxide

20. PROPERTIES IONIC COVALENT BAG OF MAGNETS
High Melting and Boiling Points
It takes a lot of NRG to separate the molecules from each other
STRONG Intermolecular Force
BAG OF GOLF BALLS
Low Melting and Boiling Points
It is easy to separate the molecules
WEAK Intermolecular Forces

21. WHEN DISSOLVED IN WATER*
IONIC
COVALENT
Ions are attracted to the water’s negative and positive poles = DISSOCIATE
Ions Separate
FYI Pure Water does not conduct Electricity. There are no ions in it to conduct a charge
Molecules do not separate, but they spread out from one another = DISSOLVE

23. WATER IS POLAR WATER IS A COVALENT COMPOUND WATER IS NEUTRAL OVERALL
OXYGEN AND HYDROGEN DO NOT SHARE ELECTRONS EVENLY
ONE END OF THE WATER IS MORE NEGATIVE THAN THE OTHER

24. Online Quiz via Classroom before next class!