1. The Structure of Matter
CH. 6
The Structure of Matter

2. Ch. 6 Section 1 Notes
Compounds and Molecules Pg

3. Chemical Bonds
The forces that hold atoms or ions together in a compound are called chemical bonds.
Can be broken, and the atoms rearrange

4. Chemical Structure
The structure of a building is the way the building’s parts fit together
A compound’s chemical structure is the way the atoms are bonded to make the compound

5. Some models represent bond lengths and angles.
Bond length is the distance between the nuclei of two bonded atoms
If a compound has 3 or more atoms, a bond angle (the angle formed by two bonds to the same atom) tells which way there atoms point.

6. Atoms are often represented by a ball-and-stick model to help you understand the compounds structure.
Structural formulas also show the structures of compounds.
Chemical symbols are used to represent the atoms
Space-filling model is another way to represent a water molecule.
Shows the space that the oxygen and hydrogen atoms take up, or fill

7. The chemical structure of a compound determines that properties of that compound.
Compounds with network structures are strong solids.
Ex: quartz
The strong bonds make the melting and boiling point of quartz and other minerals very high

8. Some networks are made of bonded ions.
Ex: Table Salt (NaCl)
Found in the form of regularly shaped crystals
Made of a repeating network connected by strong bonds
Oppositely attracted ions
High melting and boiling point

9. Some compounds are made of molecules.
Ex: sugar
Molecules attract each other and form crystals
Nitrogen, Oxygen, and Carbon Dioxide
--Gases that are made of molecules
--Atoms are strongly attracted to each other and are bonded

10. The strength of attractions between molecules varies.
Sugar, water and Dihydrogen sulfide are all compounds made of molecules but have different properties
*The higher the melting point, the stronger the attraction between the atoms

11. Hydrogen Bond
Oxygen atom of a water molecule is attracted to a hydrogen atom of another molecule
Strong bonds within each water molecule
Weaker attractions between water molecules

12. Ch. 6 Section 2 Notes
Ionic and Covalent Bonding Pg

13. Why do Chemical Bonds Form?
Atoms join to form bonds so that each atom has a stable electron configuration.
One similar to a noble gas
There are two kinds of chemical bonding:
Ionic Bonding
Covalent Bonding

14. Electrical conductivity Melting and boiling points
Ionic Compounds
Covalent Compounds
Structure
Network of bonded ions
Molecules
Valence Electrons
Transferred
Shared
Electrical conductivity
Good (when melted or dissolved)
Poor
State at room temp.
Solid
Solid, liquid, or gas
Melting and boiling points
Generally high
Generally low

15. Ionic Bonds
Form from the attractions between such oppositely charged ions.
Formed by the transfer of electrons
Oppositely charged ions bond (NaCl)

16. Ionic compounds are in the form of networks, not molecules.
The formula unit of one sodium ion and one chloride ion is NaCl
NaCl ratio is 1:1
CaF2 is 1:2
When melted or dissolved in water,
ionic compounds conduct electricity.
Ions are free to move
when not is solid form.

17. Covalent Bonds
Compounds that are made of molecules, such as water and sugar have covalent bonds.
Atoms joined by covalent bonds share electrons.
Usually form between nonmetal atoms.

18. Can be solid, liquid or gas Low melting points
MOST do not conduct electricity (not charged)
Example: Cl2
Each has 7 valence electrons.
Share one electron to have 8 valence electrons and become stable.

19. Atoms may share more than one pair of electrons.
When drawing the electron dot diagram, a line — means that there are 2 electrons being shared.
If there is two lines ==, that is a double covalent bond (4 electrons being shared)
A triple covalent bond is
formed by bonding two
nitrogen atoms
(total of 6 electrons)

20. Atoms do not always share electrons equally.
When electrons are shared equally, they are called nonpolar covalent bonds.
Ex: Cl2
When two atoms of different elements share electrons, the electrons are not shared equally and forms a polar covalent bond.
Ex: NH3

21. Metallic Bonds
Metals are flexible and conduct electric current well because their atoms and electrons can move freely throughout a metal’s packed structure.
Atoms in metals such as copper form metallic bonds.

22. Polyatomic Ions
Acts as a single unit in a compound, just as ions that consist of a single atom do.
Groups of covalently bonded atoms that have a positive or negative charge as a group.
Both covalent and ionic bonds
There are many common polyatomic ions.

23. Parentheses group the atoms of a polyatomic ion.
A polyatomic ions charge applies not only to the last atom in the formula but to the whole ion.
A polyatomic ion acts as a single unit in a compound

24. Most end with –ite or –ate
Some names of polyatomic anions relate to the oxygen content of the anion.
Most end with –ite or –ate
-ate ending usually used to name an ion that has 3 oxygen atoms
Examples: sulfate (SO42–), nitrate (NO3–), chlorate (ClO3–)
2 or less oxygen atoms have an –ite ending
Examples: sulfite (SO32–), nitrite (NO2–), chlorite (ClO2–)
Hydroxide and Cyanide are exceptions to the rules.

25. CH. 6 Section 3 Notes
Compound Names and Formulas Pg

26. Naming Ionic Compounds
Formed between cations and anions
The names of ionic compounds consist of the names of the ions that make up the compounds.

27. Names of cations include the elements of which they are composed.
Usually the name of the element
Ex: sodium forms a sodium ion

28. Names of anions are altered names of elements.
The difference is the name’s ending
Usually with the ending –ide
Compounds with Oxygen atoms have –ate, or –ite endings
An ionic compound must have a total charge of zero.

29. Some cation names must show their charge.
Transition metals may form several cations (each will have a different charge).
Iron forms a +2 ion AND a +3 ion
This is shown by placing the charge of the cation as a Roman numeral in parentheses.
Iron (II) ion and Iron (III) ion
FeO --- Iron (II) Oxide
Fe2O Iron (III) Oxide

30. Determining the charge of a transition metal cation.
The total charge of the compound MUST be zero.
Fe2O3
Three oxide ions have a total charge of (each oxygen ion has a charge of (3)=6-)
So, the total charge of the cation must be 6+

31. Writing Formulas for Ionic Compounds
If you are given the compound’s name: you can find the formula
If you are given the formula: you can find the charge of each ion

32. Naming Ionic Compounds Rules
If you are given the Name:
1. Find the symbol of each element
2. Find the charge of each ion
3. Criss-cross Method
4. If one of the ions is a Polyatomic Ion, put parentheses around it!!
Calcium Chloride
Ca, Cl
Ca+2 , Cl -1
CaCl2
This is not a polyatomic Ion
This is a polyatomic Ion

33. Naming Ionic Compound Rules:
If you are given the formula:
1. Determine if the FIRST ion is a Transition metal. If so, you MUST find it’s charge!
2. Find the name of each of the ions
3. The cation is the same as it is on the periodic table
4. The anion has an –ide ending (unless it is a polyatomic ion)
AgF
Since there is no subscript number the charges for both must be 1.
Ag is Silver, F is Flourine.
F is in group 17 and has a -1 charge so, Ag is the cation.
Silver Flouride

34. To find the charge of ions in a chemical formula:
Determine the ratio of the given formula
Separate the ions
Determine each of their charges
If the cation is a transition metal, use the criss-cross method and then look at it’s ratio.
Compare to the original ratio. What ever you do to the first element, you must do the the 2nd.
CrO2
1:2 ratio
Cr O2
Cr +4 O-2
Cr2O4 Ratio is 2:4
Reduce the ratio to 1:2

35. Math Skills “Writing Ionic Formulas” Practice Problems 1-3 Pg. 193
Lithium oxide
Li+1 O-2
Li2O
Beryllium chloride
Be+2 Cl-1
BeCl2
Titanium (III) nitride
Ti+3 N-3
TiN

36. Naming Covalent Compounds
For covalent compounds of two elements, numerical prefixes tell how many atoms of each element are in the molecule.
Numerical prefixes are used to name covalent compounds of two elements.
If there is only one atom of the first element, the name does not get a prefix.

37. Number of Atoms
Prefix 1
Mono- 2
Di- 3
Tri- 4
Tetra- 5
Penta- 6
Hexa- 7
Hepta- 8
Octa- 9
Nona- 10
Deca-

38. BF3
Boron Trifluoride
N2O4
Dinitrogen tetroxide

39. Empirical Formulas
Chemical formulas that are unknown are determined by figuring out the mass of each element in the compound.
Once the mass of each element is known, scientists can calculate the compound’s empirical formula, or simplest formula.
An empirical formula tells us the smallest whole-number ratio of atoms that are in a compound.

40. Different compounds can have the same empirical formula.
Molecular formulas are determined from empirical formulas.
A compound’s molecular formula tells you how many atoms are in one molecule of the compound.
Masses can be used to determine the empirical formula.
Convert the masses to moles. Then, find the molar ratio to give you the empirical formula.

41. Pg.196
Math Skills “Finding Empirical Formulas”
One mole of an unknown compound has g of Carbon and 6.04g of hydrogen. What is the compound empirical formula.

42. Section 3 Review # 1, 5
Name the following ionic compounds, and specify the charge of any transition metal cations.
FeI2
Iron(II) Fluoride
MnF3
Manganese(III)Flouride
CrCl2
Chormium(II) Chloride
CuS
Copper(II) Sulfide
5. Determine the chemical formulas for the following ionic compounds.
Magnesium sulfate
MgSO4
Rubidium bromide
RbBr
Chromium(II) fluoride
CrF2
Nickel(I) carbonate
Ni2CO3

43. Ch. 6 Section 4 Notes
Organic and Biochemical Compounds Pg

44. Organic Compounds
An organic compound is a covalently bonded compound that contains carbon.
Most contain hydrogen.
Oxygen, nitrogen, sulfur, and phosphorus can also be found in organic compounds.

45. Carbon atoms form four covalent bonds in organic compounds.
A compound made of only hydrogen and carbon atoms is known as a hydrocarbon.
Methane, CH4 is an example
There are four single C-H bonds
A carbon atom may never form more than 4 bonds at a time.

46. Alkanes are hydrocarbons that have only single covalent bonds.
Can have C-C bonds as well as C-H bonds
Methane is the simplest alkane

47. Arrangements of carbon atoms in alkanes.
The carbon atoms in methane, ethane, and propane are all bonded in a single line because that is their only possible arrangement.
If there are more than 3 bonded carbon atoms in a molecule, the carbon atoms do not have to be in a single line.

48. IF they are in a single line: the alkane is a normal alkane, or n-alkane.
The condensed structural formula shows how the atoms bond.

49. Alkane chemical formulas usually follow a pattern.
Except for cyclic alkanes
The # of Hydrogen atoms is always 2 more than 2x the # of carbon atoms
CnH2n+2

50. Alkenes have double carbon-carbon bonds.
Hydrocarbons
Have at least one double covalent bond between carbon atoms. C=C
Replace the –ane ending with –ene.
Simplest alkene is ethene (ethylene)

51. Alcohols have hydroxyl (-OH) groups.
Made of oxygen, hydrogen, and carbon
Most alcohols end in –ol

52. Alcohol and water molecules behave similarly.
Methanol and methane are alike except that one of the hydrogen atoms is replace by a Hydroxyl group
Alcohol molecules are attracted to each other
Liquid at room temp; HIGH boiling points

53. Polymers
A polymer is a molecule that is a long chain made of smaller molecules.
Have repeating subunits
Polyethene, is a polymer that makes up plastic milk jugs “Poly”=many
Ethene is an alkene that has the formula C2H4.
Polyethene means “many ethenes”
The smaller molecule that makes up the polymer is called a monomer.

54. Some polymers are natural, and others are artificial.
Natural: Rubber, wood, cotton, wool, starch, protein, DNA, etc.
Human-made: Plastics or Fibers

55. A polymer’s structure determines its elasticity.
Chains are tangled and can slide past each other.
When the chains are connected to each other, the polymer’s properties are different.
Some are elastic (can stretch)
When released, returns back to its original shape.
Ex: Rubber bands

56. Biochemical Compounds
Essential to life, include carbohydrates, proteins, and DNA
Can be made by living things
Carbohydrates give you energy
Proteins form important parts of your body
Muscles, tendons, fingernails, and hair
The DNA inside your cells gives your body info about what proteins you need.

57. Many carbohydrates are made of glucose.
Carbohydrates include sugars and starches, provide energy to living things.
Sucrose (table sugar) is made of two simple carbohydrates, glucose and fructose, bonded together.
Starch is made of a series of bonded glucose molecules, and is a polymer.

58. When you eat starchy food the enzymes in your body break down the starch.
The glucose that is not needed is stored as glycogen, a polymer of glucose.
When active, glycogen breaks apart into glucose molecules and gives you energy.

59. Proteins are complex polymers of amino acids.
Proteins, which provide structure and function to parts of cells, are very complex.
Made of many different molecules that are called amino acids.
Made of carbon, hydrogen, oxygen, and nitrogen. Some contain sulfur.
20 amino acids found in naturally occurring proteins

60. Proteins are long chains made of amino acids.
The amino acids that make up a protein determine the protein’s structure and function.
Proteins are long chains made of amino acids.
Made of thousands of bonded amino acid molecules

61. DNA is a polymer that stores genetic information
DNA is a very long molecule made of carbon, hydrogen, oxygen, nitrogen, and phosphorus.
DNA is in the form of paired chains, or strands.
Shape of a twisted ladder, double helix.

62. DNA is the information that the cell uses to make proteins.
DNA monomers:
Adenine, thymine, cytosine, and guanine
Pair with other DNA monomers that are attached to the opposite strand in a predictable way