Bonds and Compounds

1
Bonds and Compounds

• How to write, name and/or draw various Chemical
  Compounds

2
Ions and Ionic Compounds

• An ion is created whenever an atom gains or loses
  an electron to become more stable like a Noble
  Gas, meaning that its valence number is now 8!
• Metals are always positive, which means that they
  lose electrons.
• Nonmetals are usually negative with a few
  exceptions, like Nitrogen which has 8 different
  ion possibilities.

3
How to make an ionic compound

• To make an ionic compound, one must combine a
  positive ion with a negative ion.
• The positive ion is ALWAYS listed first, followed
  by the negative one.
• Example Na Cl- ? NaCl
• The Key is that ALL charges must be cancelled
  out, and the overall charge on the compound MUST
  be ZERO!!

4
Criss-Cross Method

• When the ratio is one-to-one or two-to-two, it is
  easy to cancel the charges. However, it can
  become a little more complicated, so scientists
  use the Criss-Cross Method to help illustrate how
  the math is done.
• Example
• Fe3 SO42- Fe2(SO4)3

5
Naming Ionic Compounds

• The first part of the name comes directly from
  the first ion in the compound.
• The second part of the name has the base of the
  second ion, but MUST end in ide, -ate, or ite.
  
• Examples
• NaCl Sodium Chloride
• K2CrO4 Potassium Chromate
• Al2(SO3)3 Aluminum Sulfite

6
Writing the formula from the name

• Unfortunately, there is no shortcut to this. You
  MUST learn the ion to know what their charges are
  to write the formula from the names. It takes
  practice and perseverance.
• Examples
• Calcium Carbonate CaCO3
• Ammonium Phosphate (NH4)3PO4

7
Review and Practice

• Name the following ionic compounds
• (NH4)3PO4
• CaSO4
• Write the formulas for the following ionic
  compounds
• Tin (IV) Fluoride
• Iron (III) peroxide

8
More Practice

• Write the formulas for the following ionic
  compounds
• Magnesium Hydroxide
• Copper (I) Sulfate
• Lead (II) Phosphate
• Ammonium Dichromate
• Zinc Acetate
• Iron (II) Oxide
• Mercury (I) Chloride
• Silver Nitrate

9
Covalent or Molecular Compounds

• Covalent compounds are created using covalent
  bonds. A covalent bond involves the sharing of
  electrons between two different atoms. These
  atoms can be the same type of atoms or different.
  
• To show the sharing of electrons, scientists use
  Lewis Dot Structures and structural formulas that
  use dashes for bonds.

10
Naming Covalent Compounds
Number Prefix
1 Mono-
2 Di-
3 Tri-
4 Tetra-
5 Penta-
6 Hexa-
7 Hepta-
8 Octa-
9 Nona-
10 Deca-

• To name covalent compounds, one must know ten
  important prefixes. These prefixes indicate how
  many of each atom is present in the molecule that
  has been created.

11
Naming them

• First, you must see if the two atoms are
  nonmetals. If so, then you have a covalent
  compound. (Be careful not to mistake an ion for
  an atom!)
• Second, note how many of each atom is present in
  the compound.
• Third, choose the prefix that will work for the
  name. (The first atom only gets a prefix if
  there is more than one the second atom ALWAYS
  gets a prefix.)
• Fourth, name it using the prefixes as needed.
  (Be carefulsome compounds have common names that
  are the preferred names.

12
Examples

• CO2 Carbon dioxide
• H2O Dihydrogen monoxide (Water)
• NH3 Nitrogen trihydride (Ammonia)
• P4O10 Tetraphosphorus decoxide

13
Types of Chemical Reactions

• There are five major types of reactions.
• These reactions are found in nature and can be
  manmade.
• In addition, these reactions often take in heat
  or energy (endothermic) or release heat or energy
  (exothermic).

14
Synthesis Reactions

• These reactions have two or more reactants that
  come together to form ONE product.
• Generic equation
• A B ? AB
• Example
• 2H2 O2 ? 2H2O

15
Decomposition Reactions

• These reactions involve ONE reactant breaking
  down to form two or more products.
• Generic Equation
• AB ? A B
• Example
• RhO3 ? RhO O2

16
Single-Replacement Reactions

• These reactions require a single atom combined
  with a compound to then form a new compound and a
  new singular atom. (Governed by the Activity
  Series of Metals)
• Generic Equation
• A BC ? AC B
• Example
• 2Li H2SO4 ? Li2SO4 H2

17
Double-Replacement Reactions

• These reactions involved two ionic compounds
  cations switching anion partners to form new
  compounds. (A gas or precipitate usually
  forms!)
• Generic Equation
• AB- CD- ? AD- CB-
• Example
• AgBr NaCl ? AgCl NaBr

18
Combustion Reactions

• All combustion reactions involve oxygen gas as a
  reactant and the release of great amounts of
  energy as a product. There are types of
  combustion reactions Metals with oxygen to form
  metal oxides and hydrocarbons with oxygen to form
  carbon dioxide and water.

19
Combustion Reactions (cont.)

• Examples of both combustion reactions
• 2Mg O2 ? 2MgO light
• C2H4 3O2 ? 2CO2 2H2O energy