1. Chapter 7 & 8
Ions and Bonding

2. Groups have…
Similar properties
Same number of valence electrons

3. Octet Rule Atoms try to achieve the configuration of a noble gas
They want 8 valence electrons
Octet= set of 8

4. Metals…
Form cations by losing electrons

5. Nonmetals…
Form anions by gaining electrons

6. Bonds Between Atoms
Polyatomic Ions
Ionic
Covalent
Metallic

7. Forming of a bond is like marriage
Less stable
Endothermic
More stable
Exothermic
The breaking of a bond relates to a divorce

8. Ionic Compound is composed of a cation and an anion
usually a metal and a nonmetal
composed of ions but neutral
Examples: NaCl Table Salt

10. Ionic Compounds Are usually crystalline solids at room temperature
Beryl
Fluorite
Aragonite

11. Ionic Compounds Usually have high melting points
Can conduct electricity when melted or dissolved in water

12. Ionic Compounds
Ions are strongly bonded together.
Structure is rigid.

13. Ionic Bond
Electrostatic forces that hold the ions of an ionic compound together

14. Ionic Bonding Na Cl
The metal (sodium) tends to lose its one electron from the outer level.
The nonmetal (chlorine) needs to gain one more to fill its outer level, and will accept the one electron that sodium is going to lose.

15. Ionic Bonding

16. Do they Conduct?
Conducting electricity means allowing charges to move.
In a solid, the ions are locked in place.
Ionic solids are insulators.
When melted, the ions can move around.
Melted ionic compounds conduct.
NaCl: must get to about 800 ºC.
Dissolved in water, they also conduct (free to move in aqueous solutions

17. - Page 198
The ions are free to move when they are molten (or in aqueous solution), and thus they are able to conduct the electric current.

18. Metallic Bonds Metals hold on to their valence electrons very weakly
Metal atoms are compact and ordered
Zinc
Gold

19. Metallic Bonding Name 4 Characteristics of a Metallic Bond.
1. Good conductors of heat and electricity
2. Great strength
3. Malleable and Ductile
4. Luster
- A metallic bond occurs in metals. A metal consists of positive ions surrounded by a “sea” of mobile electrons.
This shows what a metallic bond might look like.

20. Alloy
homogeneous mixture of metals

21. Alloys We use lots of metals every day, but few are pure metals
Alloys are mixtures of 2 or more elements, at least 1 is a metal
Made by melting a mixture of the ingredients, then cooling
Brass: an alloy of Cu and Zn
Bronze: Cu and Sn

22. Why use alloys? Properties are often superior to the pure element
Sterling silver (92.5% Ag, 7.5% Cu) is harder and more durable than pure Ag, but still soft enough to make jewelry and tableware
Steels are very important alloys
corrosion resistant, ductility, hardness, toughness, cost

23. Covalent Bond Very strong Low melting and boiling points
-A covalent bond is a chemical bond resulting from SHARING of electrons between 2 bonding atoms.
-Formed between two nonmetals.
Very strong
Low melting and boiling points

24. Molecule…
The neutral particle is formed when atoms share electrons

25. Covalent Bonding-Diatomic Molecules

26. Diatomic Molecules
Group 7 elements
Oxygen
Hydrogen
Nitrogen

27. Molecular Formula
Shows how many atoms of each element a molecule contains
NH3

28. Covalent Bonds can have multiple bonds, so you should be familiar with the following…
Single Covalent Bond- chemical bond resulting from sharing of an electron pair between two atoms.

29. Double Covalent Bond- chemical bond resulting from sharing of two electron pairs between two atoms.

30. Triple Covalent Bond-chemical bond resulting from sharing of three electron pairs between two atoms.

31. Polar Molecule
Molecule with a positive and a negative end

32. Intermolecular Attractions
Weaker than covalent and ionic bonds
Examples:
Van der Waals Forces
Hydrogen Bonds