1. Chapter 8 Chemical Bonding

2. Section 1: Electrons & Chemical Bonding
Vocabulary
Chemical Bonding
Chemical Bond
Valence electron

3. Combining Atoms
All substances made of one or more atoms of the 100+ elements
Chemical bonding is the joining of 2 or more atoms to form a new substance

4. Combining Atoms
Chemical bond is the interaction that keeps molecules together.
Models are used since chemical bonding is complex and microscopic.

5. Electron Number & Organization
Electrons are key to bonding!!
Electrons are organized into energy levels.
Only electrons in outer energy level form bonds

6. Electron Number & Organization
Outer energy electrons are called valence electrons
Remember == elements are grouped based upon similar properties on PTOE
All atom within a group
have same # of
valence electrons

7. To Bond or Not to Bond
# of valence electrons determine if and how an atom forms bonds
All atoms want to fill their outer most energy level
Either by sharing electrons (covalent)
Or by giving/taking electrons (ionic)

8. Section 2: Ionic Bonds

9. Vocabulary
Ionic bond
Ion
Crystal lattice

10. Forming Ionic Bonds
Ionic bonds when valence electrons transfer from 1 atom to another atom

11. Forming Ionic Bonds
Normally the number of protons and electrons equal each other
No overall charge to the atom
10+ and 10- = no charge
Ions are charged atoms
Number of electrons change
Protons will never change

12. Forming Positive Ions Atoms that lose electrons form a positive ion
3 protons (+)
2electrons (-)
1+ charge

13. Forming Positive Ions
Most metals have outer energy level with a few valence electrons
Most metals form positive ions

14. Forming Positive Ions Metals tend to lose valence electrons
Takes energy to remove electrons
Groups 1 & 2 of PTOE require less energy to remove their valence electron
You’ll only find ions of these metals in nature

15. Forming Negative Ions Atoms that gain electrons are negative ions
2 protons (+)
3 electrons (-)
1- charge

16. Forming Negative Ions Atoms of nonmetals have nearly full valence
Oxygen has 6 electrons in its valence level
Needs only 2 electrons to be full
full = stable
Energy is released when electrons are gained

18. Forming Ionic Compounds
“ ide” suffix used for names of compounds formed from negative compound
number of electrons lost = number of electrons gained by non-metal
New compound is neutral in charge

19. Forming Ionic Compounds
Ionic Compound is a chemical change
All chemical changes = new properties
New properties are different from original

20. Forming Ionic Compounds
Ionic compounds form a crystal lattice
Repeating 3-Dimensional pattern
Other properties
Brittle solids
High melting points
Very high boiling points
Highly soluble in water

21. Covalent and Metallic Bonds
Section 3:
Covalent and Metallic Bonds

22. Vocabulary
Covalent bond
Molecule
Metallic bond

23. Covalent Bonds Chemical bond formed when atoms share electrons
Formed between two non-metals atoms

24. Covalent Bonds Covalent bonds are formed from molecules
Molecules = 2 or more atoms joined together in a
definite ratio

25. Covalent Bonds Electron-dot diagrams
Representation/model of valence electrons
Used to predict number of bonds an atom might form

26. Covalent Bonds Electron-dot diagrams uses octet rule Octet = 8
8 valence electrons = stability

27. Covalent Compounds & Molecules
Atom = smallest particle that an element can be divided and still be that element
Molecule = smallest particle that a covalently bonded compound can be divided and still be that same compound

28. Covalent Compounds & Molecules
Molecules are at least 2 covalently bonded atoms
Some elements are only found in molecules in nature
Called diatomic elements
Oxygen
Nitrogen
All halogens

29. Covalent Compounds & Molecules
More complex molecules formed from multiple atoms
Carbon is common atom to form complex molecules
1 Carbon can make
up to 4 bonds

30. Metallic Bonds
Metallic bond forms between positive metal ion and electrons
in metal bonds, atoms are close together
Outermost energy levels overlap
Valence electrons can move throughout metal

31. Properties of Metal
Due to metallic bonds, metals have unique properties
Conduct electric current
Ductile  drawn into wires
Malleable  able to be pounded/shaped
Bends without breaking

32. to do your vocabulary!