1. Ionic Compounds and Metals

2. Types of bonds
A chemical bond is the force that holds atoms together in a molecule.
Ionic bonds form when electrons are transferred between atoms.
Covalent bonds form when electrons are shared between atoms.

3. Electronegativity
Electronegativity is a measure of the attraction a bonded atom has for electrons.
Electronegativity increases from bottom to top and from left to right.

4. Formation of Ionic Bonds
If the electronegativity difference is large (a metal with a nonmetal) an ionic bond will form.
Ionic bonds are the strongest type of bond.
Substances resulting from ionic bonds are classified as crystalline solids.

5. Let’s Practice
Identify the type of bond (ionic or covalent) that will form between each pair of atoms.
Na and Cl
C and O
N and H
Ca and O
K and N
Mg and F

6. Example

7. Forming Ions
When neutral atoms gain or lose valence e- an ion is formed.
Ions are atoms with a charge
Cations have a positive charge (K+, Li+)
Anions have a negative charge (F-, I-)

8. Ions forming bonds
Cations are attracted to anions because of opposite charges.
“Opposites attract”

9. Why do ions form?
Ions form to attain a more stable electron configuration.
Remember that a Noble gas configuration is the most stable
Ne - ___ ___ ___ ___ ___
1s 2s 2p
All Noble Gases have a full octet (8 valence e-)

10. Noble Gases

11. Why do ions form? Na __ __ __ __ __ __ 1s 2s 2p 3s
Now Na+ looks like neon
Ne __ __ __ __ __
1s 2s p
All atoms are trying to have a Noble Gas electron configuration so, they will lose or gain electrons to get there

12. Why do ions form? F __ __ __ __ __ 1s 2s 2p F- __ __ __ __ __ 1s 2s 2p
Ne __ __ __ __ __

13. Review
Draw the dot notation for each element and the charge of its ion N S Ba Li

14. Ionic Bonds
Ionic bonds- the force that holds two oppositely (+ and -) charged particles together.
Ionic compounds contain ionic bonds and are neutral
Usually forms between a metal and a nonmetal

15. Forming Ionic Bonds

16. Forming Ionic Compounds
Write an equation showing how ionic compounds are formed for the following elements.
Na and I
Mg and O
Al and Cl

17. Properties of Ionic Compounds Shape
The Ionic bond produces unique characteristics for ionic compounds
Crystals are created by repeating patterns of cations and anions. This balances the forces between the ions.
This is called a crystal lattice

18. Properties of Ionic Compounds Physical Properties
Electrolytes (aqueous ions- Ions dissolved in water) conduct electricity
Solid ionic compounds DO NOT conduct electricity because the charges are locked in place

19. Properties of Ionic Compounds Physical Properties
Ionic solids are strong and hard to break apart
High Melting points
High Boiling points
Transition metals in the crystal give the ionic solid color.

20. Properties of Ionic Compounds Physical Properties
The solid ionic crystals are hard, rigid, and brittle
The strong forces between ions produce this property

21. Ionic Compounds
Ionic compounds are repeating patterns of the cation and anion.
The simplest ratio of ions involved is called a formula unit.
NaCl is the formula unit for table salt

22. Ions in Ionic Compounds
Monatomic ions- ions made of only one type of atom (Cl-, F-, Li+)
Polyatomic ions- ions made of at least two different types of ions (OH-, NH4+)
Cation + Anion  Ionic Compound

23. Writing formulas for ionic compounds
Binary ionic compounds contain a single cation and anion. Remember that the final compound must be neutral so the charges must balance.
Ca+2 Cl-  CaCl2

24. Cris-Cross method Record the ion symbol and charge
The # of the charge of the cation becomes the subscript for the anion and the # of the charge for the anion becomes the subscript for the cation. The #1 does not have to be recorded it is understood.
Al O-2  Al2O3

25. Cris-Cross method
Al2O3 is the formula unit for aluminum oxide. The subscripts indicate how many ions are needed of each in order to balance the charges.
The formula unit consists of 2Al3+ ions and 3O2- ions. (6 positive charges cancel out 6 negative charges resulting in a neutral compound)

26. Try a few Potassium and Iodide K1+ I1-  KI Magnesium and chloride
Mg2+ Cl1-  MgCl2
Aluminum and bromide
Al3+ Br1-  AlBr3
Cesium and nitride
Cs1+ N3-  Cs3N

27. Naming Ionic Compounds
NaBr
Name the cation then the anion. Cations are always written first
Monatomic cations always keep their name. If the cation is an ion that may carry multiple charges then a roman numeral is used to indicate which charge the cation is carrying. [Fe+3 (III) and Fe+2 (II)].
Note: Cations that are not located in groups 1A, 2A, or 3A, require a roman numeral.

28. Naming Ionic Compounds
The monatomic anion’s ending is changed to -ide. Fluorine is changed to Fluoride.
NaBr-
sodium bromide
Fe3N2 –
Iron (II) nitride
Note: Cris cross the subscripts back up to determine the charges: Fe3N2 Fe2+N3-

29. Let’s practice CaCl2 Calcium chloride K2O Potassium oxide CuCl2
Copper (II) chloride
Fe2O3
Iron (III) oxide

30. What about Polyatomic ions?
Al+3 and PO4-3  AlPO4
The same rules apply, however NEVER CHANGE A SUBSCRIPT THAT IS ALREADY THERE.
Polyatomic ions may also require () around them if there is a need for more than one to balance the charge

31. Examples Write the formula for copper (II) sulfate. Cu2+
Look up sulfate on the table and record the formula
SO42-
Apply the cris cross method as usual.
Cu2+SO42-  CuSO4

32. Another Example Iron (II) nitrate Fe2+ Look up nitrate on the table
Apply the cris cross method as usual
Fe2+NO31-  Fe(NO3)2

33. Naming compounds containing polyatomic ions
Write the name for Al2(SO4)3
name the cation
Look up the polyatomic ion on the table and write its name (Do not change the ending)
aluminum sulfate
Try this one: Na3PO4
Sodium phosphate

34. Metallic Compounds Compounds containing only metals
Form lattice crystals as solids

35. Metallic Bonds Metals do not give away or take on valence electrons.
They do not share electrons to make bonds either.
Electrons from metals overlap and create a sea of electrons that bond metal atoms

36. Metallic Bonds
The electrons are free to move between atoms (delocalized electrons)
As an electron moves from one atom to the next it creates a cation which “bonds” the atoms together creating a metallic bond.

37. Properties of Metals Metals Usually have high melting points.
Metals usually have high boiling points
Why?

38. Properties of Metals
Malleable- ability to be hammered into a thin sheet
Ductile- ability to be stretched into a thin wire
Durable-long lasting
Why?

39. Properties of Metals Good conductors of heat
Good conductors of electricity
Why?

40. Properties of Metals
Metals are strong and hard
Why?

41. Alloys Alloys are mixtures of metals
Ex: stainless steel, brass, cast iron
Properties of alloys are similar to those of its elements. Alloys tend to be stronger than the element