1. Chapter 5 Ionic/Covalent Compounds and Nomenclature

2. Ions
Remember: an element has a certain number of protons, and that never changes…
But an element can have different numbers of neutrons and electrons.
We call elements with unusual numbers of electrons ions

3. Example: Helium Ions
In its natural state, Helium has 2 Protons, 2 Neutrons, and 2 Electrons
Atomic Charge
Protons (2) = +2
Neutrons (2) = 0
Electrons (2) = - 2
-----
TOTAL CHARGE = 0

4. This is now a POSITIVE ION, also called a CATION
Example: Helium Ions
If Helium loses an electron, it still has 2 Protons and 2 Neutrons, but now only 1 Electron
Atomic Charge
Protons (2) = +2
Neutrons (2) = 0
Electrons (1) = - 1
----TOTAL CHARGE
This is now a POSITIVE ION, also called a CATION

5. This is now a NEGATIVE ION, also called an ANION
Example: Helium Ions
If Helium gains an electron, it still has 2 Protons and 2 Neutrons, but now has 3 electrons
Atomic Charge
Protons (2) = +2
Neutrons (2) = 0
Electrons (3) = - 3
-----
TOTAL CHARGE = - 1
This is now a NEGATIVE ION, also called an ANION

6. Writing Elements as Ions
Helium with a charge of -1
He-
Cation or Anion?

7. Example: Helium Ions
Helium with a charge of +1
He+
Cation or Anion?

8. He+2 (Helium without electrons) is also called an “Alpha Particle”
Example: Helium Ions
Helium with a charge of +2
He+2
He+2 (Helium without electrons) is also called an “Alpha Particle”

9. Now you try… Check one: What’s its symbol? ___ Cation (C+)
Carbon gains an electron and becomes an ion…
Atomic Charge
# of Protons _____ Total Proton Charge _____
# of Neutrons _____ Total Neutron Charge _____
# of Electrons _____ Total Electron Charge _____
TOTAL CHARGE = ______
Check one: What’s its symbol?
___ Cation (C+)
___ Anion (C-)
___ Not an Ion (C)

10. Now you try… Check one: What’s its symbol? ___ Cation (Sc+)
Scandium loses an electron and becomes an ion…
Atomic Charge
# of Protons _____ Total Proton Charge _____
# of Neutrons _____ Total Neutron Charge _____
# of Electrons _____ Total Electron Charge _____
TOTAL CHARGE = ______
Check one: What’s its symbol?
___ Cation (Sc+)
___ Anion (Sc-)
___ Not an Ion (Sc)

11. Being an Isotope and an Ion
5Li+ 3
What’s the atomic charge?
How many neutrons in the nucleus?

12. Symbolic Convention for AtomsX Z
X = Atomic Symbol
A = Mass Number/Isotope (protons + neutrons)
Z = Atomic Number (protons)
i = Ionization Number (protons – electrons)*
* Not shown if zero, sign only shown if +1 or -1

13. Co +2 59 27 Find these: Atomic Symbol Mass Number Atomic Number
Ionization Number
Protons
Neutrons
Electrons
Anion or Cation +2 59 Co 27

14. Rf - 251 104 Find these: Atomic Symbol Mass Number Atomic Number
Ionization Number
Protons
Neutrons
Electrons
Anion or Cation -
251 Rf
104

15. C 13 6 Find these: Atomic Symbol Mass Number Atomic Number
Ionization Number
Protons
Neutrons
Electrons
Anion or Cation 13 C 6

16. 5.3 Compounds
Molecule- An electrical neutral group of atoms that act as a unit.
Molecular Compound- Composed of more than one molecule. Ex: Water
Ionic Compounds- Composed of positive and negative ions.
Electrically neutral
Formed from metals & nonmetals
Most are crystalline solids at room temperature

17. A shorthand way of listing the elemental ingredients of a molecule
Chemical Formula:
A shorthand way of listing the elemental ingredients of a molecule
Although it gives you the composition, it tells you nothing about its structure.

18. Chemical Formula Examples: H2O2 (Hydrogen Peroxide)

19. Chemical Formula Examples: C6H12O6 (Dextrose or “Corn Sugar”)

20. Chemical Formula Examples:
Common Name
Chemical Formula
Molecular Structure
Ingredients
Water
H20
1 Part Oxygen
2 Parts Hydrogen

21. Chemical Formula Examples:
Common Name
Chemical Formula
Molecular Structure
Ingredients
Table Salt
NaCl
1 Sodium Atom
for each…
1 Chlorine Atom

22. Chemical Formula Examples:
Common Name
Chemical Formula
Molecular Structure
Ingredients
Asprin
C9H8O4
9 Carbon Atoms
8 Hyrdogen Atoms
4 Oxygen Atoms

23. Hemoglobin (part of blood)
Chemical Formula Examples:
Common Name
Chemical Formula
Molecular Structure
Ingredients
Hemoglobin (part of blood)
C3032H4816O780N780S8Fe4
Seriously?
3,032 Carbon Atoms
4,815 Hydrogen Atoms
780 Oxygen Atoms
780 Nitrogen Atoms
8 Sulfur Atoms
4 Iron Atoms

24. Diatomic Molecules Some elements commonly exist as molecules
Contain two atoms of the same element
H, O, N, F, Cl, Br, I

25. Chemical Formula Examples:
NOTE: While chemists usually put atomic symbols in a certain order in a chemical formula, the order doesn’t make a difference to what molecule you have.
EXAMPLE:
NaHCO3 = CHO3Na
(Baking Soda)
Because of the…

26. Law of Definite Composition
No matter how it’s formed, a particular compound always has the same type and number of elements in it.
Soooo… A compound with a certain ratio of elements in it is always the same compound no matter how or when it’s formed.
It’s like a chocolate cake recipe…if you want the cake to be the same every time you make it, you have to use exactly the same ingredients in exactly the same amounts every time.

27. Number of Atoms in Molecule Number of Elements in Molecule
Complete the table:
Common Name
Chemical Formula
Ingredients
Number of Atoms in Molecule
Number of Elements in Molecule
Hydrogen Peroxide
H2O2
___ Oxygen Atoms
___ Hydrogen Atoms
Bleach
1 Sodium Atom
1 Carbon Atom
1 Iodine Atom
1 Oxygen Atom
Rubbing Alcohol
C_H8O_
3 Carbon Atoms

28. Like brownies and chocolate cake.
But…
Some compounds have the same ingredients (molecules), but different ratios of those ingredients.
Like brownies and chocolate cake.

29. Law of Multiple Proportions
For two compounds that are made up of the same elements in different ratios, those ratios of atoms will be simple whole numbers.
Example: Carbon Monoxide (CO) and Carbon Dioxide (CO2) have Carbon and Oxygen in common, in the ratios 1 to 1 (for Carbon) and 1 to 2 (for Oxygen).

30. What are their molecular formulas and elemental ratios?
Law of Multiple Proportions Example
Any idea what these are?
(HINT: Red is Oxygen, White is Hydrogen)
What are their molecular formulas and elemental ratios?

31. Law of Multiple Proportions Example
Hydrogen Peroxide
H2O2
Water
H2O
Hydrogen Ratio = 2:2
Oxygen Ratio = 2:1

32. Ionic Compounds
Chemical formulas written for ionic compounds do not represent a molecule.
Ex. NaCl
Ions are arranged in an orderly pattern, but there are many more than just 1 Na and 1 Cl atoms.
Scientists use a FORMULA UNIT- the lowest whole-number ratio of ions.
NaCl= 1:1 ratio between sodium and chlorine ions

33. 8.2 Formation and Nature of Ionic Bonds
Properties of ionic compounds
Crystalline solids with high melting points
Brittle
Usually metal and nonmetal in compound
Highly water soluble
Nonconductor as a solid
Conductor when a molten or aqueous (electrolyte)

34. 5.6 Ionic Charges
In order to write chemical formulas for ionic compounds, you need to know the types of ions that atoms tend to form.
For groups 1, 2, & The ionic charges can be easily determined by using the periodic table.
Get out your periodic tables (the colored one)… YES, we’re adding MORE!
Metals tend to lose electrons and form cations.
Nonmetals tend to gain electrons and form anions.
Groups 14 & 18 usually do not forms ions.
TRANSITION METALS- Have more than one common ionic charge

35. Let me introduce you to POLYATOMIC IONS They must be memorized!
Charge = +1
Charge = -1
Charge = -2
Charge = -3
Nitrogen Polyatomics
Ammonium: NH4+
Nitrate: NO3-
Nitrite: NO2-
Carbon Polyatomics
Cyanide: CN-
Carbonate: CO3-2
Acetate: CH3COO-
Oxalate: C2O4-2
Metal Polyatomics
Permanganate: MnO4-  
Chromate: CrO4-2
Dichromate: Cr2O7 –2
Other Polyatomics
Hydroxide: OH-
Sulfate: SO4-2
Phosphate: PO4-3
Chlorate: ClO3-
Electron Shortage
Electron Abundance

36. WHAT ARE THEY???
Polyatomic Ions are tightly bound groups of atoms that behave as a unit and carry a charge.
Names & table on page 123 in your books!

37. 8.3 Names and Formulas for Ionic Compounds
The formula of an ionic compound is the fewest cations and anions needed to make the total charge zero.

38. 5.9 – Writing Formulas- Binary Ionic Compounds
Binary compounds- composed of two elements
Electrically neutral
Positive charges must exactly balance the negative charges
Net ionic charge must be zero
Example: Potassium Chloride
K+ Charge= +1
Cl- Charge = -1
Overall Charge = 0
Net Formula = KCl

39. Your turn…
Calcium Bromide
Iron (III) Oxide
Aluminum Iodide

40. Wait…. Look back at what you just did…
Does anybody notice any patterns????
INTRODUCING …
The “crisscross” method
The numerical charge of each ion is crossed over and used as a subscript for the other ion. The signs of the numbers are dropped.
Let’s try one…. Ca & S
One More… Na & O

41. 5.11 Ternary Ionic Compounds
Contains atoms of three different elements
They usually contain a polyatomic ion.
So how would you write the formula for a ternary compound??
The procedure is the same as binary ionic compounds.
Write down the formula for each ion
Balance the charges
Use parentheses if you have more than one of a polyatomic ion
Examples:
Ca & NO3 Mg & OH

42. 8.3 Names and Formulas for Ionic Compounds
What is the formula of iron(III) sulfate?
iron(III) = Fe3+
sulfate = (SO4)2-
(SO4)2-
(SO4)2-
(SO4)2-
Fe3+
Fe3+ +3 +3 2- 2- 2-
= 0
Fe2(SO4)3

43. Nomenclature
Nomenclature – A universally accepted system used for assigning names to chemical compounds.
IUPAC – International Union of Pure and Applied Chemistry. The folks responsible for nomenclature rules and the periodic table.

44. Naming Ionic Compounds
Binary Ionics of Metals That Aren’t Transition Elements
Examples: BaO, NaCl, Mg2F
Step
Example (NaCl)
1 – Full name of the metal (Cation)
Sodium
2 – Add the root of the non-metal (Anion)
Sodium Chlor
3 – Add “ide”
Sodium Chloride
What would these be?
BaO Mg2F CaCl2 MgO

45. 8.3 Names and Formulas for Ionic Compounds
Transition Metal Ions
Many transition metals can be stable at several charges.
Use roman numerals and parenthesis to distinguish between different ions.
Fe Fe3+
iron (III)
iron (II) 2+ 3+

46. Naming Ionic Compounds
Binary Ionics of Metals That ARE Transition Elements
Examples: Cr2O3, NiS, Cu2O
Step
Example (Cr2O3)
1 – Full name of the metal (Cation)
Chromium
2 – Roman numeral for the cation charge
Chromium(III)
3 – Add the root of the non-metal (Anion)
Chromium(III) Ox
4 – Add “ide”
Chromium(III) Oxide
What would these be?
NiS Ni2S3 TiO2

47. Naming Ionic Compounds
Binary Ionics of Metals and Polyatomic Ions
Examples: NaNO3, Al2(SO4)3, NH4Cl
Step
Example: Pb(CO3)2
1 – Full name of the Cation
Lead
2 – Roman numeral for the cation charge if there could be more than one charge
Lead(IV)
3 – Add the name of the polyatomic anion
Lead(IV) Carbonate
What would these be?
NaNO3 Al2(SO4)3 NH4Cl

48. Summary of Naming & Formula Writing
1. In an ionic compound, the net ionic charge is zero
2. An –ide ending generally indicates a binary compound.
3. An –ite or –ate ending usually means there is a polyatomic anion in the formula
4. Prefixes in the name generally indicate that the compound is molecular. They show the number or each atom in the formula.
5. A Roman numeral shows the ionic charge of the cation.

49. Naming Covalent Compounds Increasingly Metallic Increasingly Metallic
Stuff You Need to Know First – Most Metallic Elements
Increasingly Metallic
Increasingly Metallic

50. Naming Covalent Compounds
Stuff You Need to Know First – Greek Prefixes for Quantity
prefix
number
mono- 1
di- 2
tri- 3
tetra- 4
penta- 5
hexa- 6
hepta- 7
octa- 8
nona- 9
deca- 10

51. Naming Covalent Compounds
Examples: H2O, N2O3, CO2, N2O4, P4O10
Step
Example (N2O3)
1 – Greek prefix for the most metallic element (unless it’s oxygen, then use the other element first) [You can omit mono- here if there’s only one of the 1st element]
Di-
2 – Full name of that element
Dinitrogen
3 – Greek prefix for the other element
Dinitrogen Tri
4 – Root of the other element
Dinitrogen Triox
3 – Add “ide”
Dinitrogen Trioxide
What would these be?
H2O CO2 N2O4 P4O10

52. Molecular Compounds and Acids
“ide” anion
becomes
“hydro-” “-ic”
Common acids
Hydrochloric acid HCl
Sulfuric acid H2SO4
Nitric acid HNO3
Acetic acid HC2H3O2
Phosphoric acid H3PO4
Carbonic acid H2CO3
Nitrous acid HNO2
“-ate” anion becomes “-ic” acid
“-ite” anion would become “-ous” acid

53. Delocalized electrons around the cations
2. Metallic Substances 1 2
Metallic bond- force of attraction between free floating valence electrons and positively charged metal ions. (electron sea)1,2
Delocalized electrons around the cations
Properties of metals
Usually solids
Usually high melting point
Good conductor of heat and electricity
Malleable, ductile, and shiny

54. 2. Metallic Substances
Alloy - mixture of two or more elements (1 must be a metal).
Types of alloys
Substitutional – atoms of metal are replaced by atoms of similar size
Sterling silver, brass, 10-carat gold
Interstitial – small atoms put in between metal atoms
Carbon steel

55. Bonding Review

56. Ionic Bonding

57. Metallic Bonding