Chapter 3

Chapter 3

Chemical Compounds

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Types of Compounds

Inorganic Compounds – do not contain carbon

Organic Compounds – contain carbon

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Inorganic Compounds

Ionic compound

combination of metals and nonmetals

made up of positive and negative ions

joined together by electrostatic

forces

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Ions

Ions are atoms that have either lost or gained electrons.

Electrons are lost from the outermost energy level (discussed later in textbook)

Ions that have more protons than electrons are positively charged

Ions that have more electrons than protons are negatively charged

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Formed from a single atom

Example:Sodium Na+

Sulfur s6+ or S2-

Monatomic Ions

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Monatomic ions

Ions formed from a single atom

Atom = Na Ion = Na+

Atom = O Ion = O2-

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Using your periodic table

The number of the main group elements will be used to determine the oxidation states.

Groups IA, IIA, IIIA = +, 2+, 3+

Group VA = 5+, 3-

Group VIA = 6+, 2-

Group VIIA = 7+, -

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Alkali Metals (Group IA)

The oxidation number of alkali metals in a compound is always 1+.

Never write the number 1 for anything in chemistry. It is understood.

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Alkaline Earth Metals (Group IIA)

The oxidation number of alkaline earth metals in a compound is always 2+.

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Nitrogen Family (Group VA)

Nitrides, phosphides, and arsenides are always 3- in binary salts.

N3- P3- As3-

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Oxygen Family (Group VIA)

The oxidation number of oxygen is almost always 2- in a compound. There are exceptions.

a) Peroxides, O22- (each oxygen is 1-)

[Formed with elements in Groups IA and IIA]

b) Superoxides, O2- (each oxygen is ½-)

K, Rb and Ce are the only elements that form

Superoxides.

Sulfide, selenide, telluride, and polonide are always 2- in binary salts. (S2-, Se2-, Te2-, Po2-)

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The Halogens (Group VIIA)

In metallic halides the halogen (F, Cl, Br, I, At) always has an oxidation number equal to 1-.

Remember: Never write the number 1.

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Oxidation States for Monatomic Ions

Atom Oxidation State

Hydrogen (+) and (-)

Sodium

Barium

Aluminum

oxygen

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Oxidation State for Monatomic Ions


Hydrogen (+) and (-) H+, H-

Sodium Na+

Barium Ba2+

Aluminum Al 3+

oxygen O2-

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Balancing Using Oxidation Number

The oxidation number of any element in its free state (uncombined with other elements) is 0.

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Ionic Compounds

Ionic compounds consists of a metallic ion and a non-metallic ion.

Positive ion is the cation

Negative ion is the anion.

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Chemical Formula indicates

The elements present

The relative number of atoms of each element in the compound

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Binary Compounds

Binary compounds are made of two different element.

-Combined chemically

-Definite proportion by mass

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Balancing Binary Compounds

Step I: Write the symbols for each ion Example: Na Cl Step II: Assign an oxidation number

Na+ Cl- Al3+ S2-

Step III: Balance the compound. The sum of the oxidation numbers must be zero. (Hint: Crisscross the charges. Don’t include the signs.)

NaCl Al2S3

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Balancing Binary Compounds

What should you do if the charges are the same?

Nothing. The formula is balanced. The sum of the charges is “0”.

Example: Ba 2+ O2- = BaO

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Balancing Binary Formulas

Silver & chlorine Zinc & oxygen Calcium & bromine Strontium & fluorine Barium & chlorine Calcium & chlorine

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Balancing Binary Formulas

Silver & chlorine AgCl Zinc & oxygen ZnO Calcium & bromine CaBr2

Strontium & fluorine SrF2 Barium & chlorine BaCl2

Calcium & chlorine CaCl2

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Naming Binary Compounds

1. Write a balanced formula

2. Write the name of the 1st ion with no

changes.

3. Change the ending on the 2nd ion to –ide.

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Example

NaCl = sodium chloride

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Silver & chlorine Zinc & oxygen Calcium & bromine Strontium & fluorine Barium & chlorine Calcium & chlorine

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Silver & chlorine silver chloride Zinc & oxygen zinc oxide Calcium & bromine calcium bromide Strontium & fluorine strontium fluoride Barium & chlorine barium chloride Calcium & chlorine calcium chloride

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Transitional Ions and Charges

Fe2+ Iron (II) Ni 2+ Au+

Fe3+ Iron (III) Ni 3+ Au 3+

Sn2+ Tin (II) Zn 2+ Ag+1

Sn4+ Tin (IV)

Cu+1 Copper (I) Pb 2+ Mn+2, +3, +4,+6,+7

Cu+2 Copper (II) Pb 4+

Co +2

Co +3

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Naming Transitional Binary Compounds

Fe2+ Iron (II) FeCl2 = iron (II) chloride Fe3+ Iron (III)

Sn2+ Tin (II) SnCl2 = tin (II) chloride Sn4+ Tin (IV)

Cu+1 Copper (I) CuCl = copper (I) chloride Cu+2 Copper (II)

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Polyatomic Ions

Polyatomic ions consist of two or more ions that act as one in a chemical reaction.

Examples:

NO3- nitrate PO4

3- phosphate

SO42- sulfate NO2

- nitrite

SO32- sulfite OH- hydroxide

ClO3- chlorate MnO4

- permanganate

C2H3O2- acetate NH4+ ammonium

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Ternary Compounds

Ternary compounds are made up of three ions. Two of the ions are joined together and act as one. (polyatomic ion)

Example: NaNO3

Na = sodium N = nitrogen O = oxygen

N & O make up the nitrate ion, NO3-

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Naming Ternary Compounds

1. Write a balanced formula

2. Write the name of the 1st ion. No changes to

name.

3. Write the name of the polyatomic ion.

NaNO3 = sodium nitrate

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Formula and Name of Ternary Compounds

MgCO3 magnesium carbonate

Pb(NO3)2 lead nitrate

Ca(OH)2 calcium hydroxide

Ba(NO3)2 barium nitrate

Fe2(SO4)3 iron (III) sulfate

LiC2H3O2 lithium acetate

KClO3 potassium chlorate

(NH4)2SO4 ammonium sulfate

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Organic Compounds

Molecular compound– Made up of a small number of different

non-metal atoms- Held together by forces known as

covalent bonds

The chemical formula gives you the number of atoms of each element contained in a single molecule of the compound

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Organic CompoundsPrefixes

Number Prefix 1 mono- 2 di-/bi 3 tri- 4 tetra- 5 penta- 6 hexa- 7 hepta- 8 octa- 9 nona- 10 deca-

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Organic Compounds

Carbon dioxide CO2

Nitrogen trioxide NO3

Dinitrogen trioxide N2O3

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Nomenclature Review Wkst.

1. calcium chloride 1. NaCl

2. magnesium oxide 2. MgCl2

3. iron (III) hydroxide 3. BaF2

4. potassium sulfate 4. KNO3

5. cesium nitrate 5. Al2S3

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Nomenclature Review

6. rubidium selenide 6. Li2O

7. strontium phosphate 7. SrSO4

8. potassium oxide 8. CuCl2

9. copper (I) oxide 9. (NH4)3PO4

10. ammonium sulfafte 10. BeBr2

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Nomenclature Review

11. sodium sulfide 11. H2SO4

12. rubidium sulfate 12. Mg3(PO4)2

13. calcium hydroxide 13. Na3PO4

14. sodium iodide 14. (NH4)2O

15. potassium hydroxide 15. AuCl3

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Nomenclature Review

16. lead (II) sulfide 16. Na2CO3

17. sodium carbonate 17. SiO2

18. iron (III) chloride 18. PbS

19. phosphoric acid 19. N2O3

20. barium sulfate 20. HNO3

21. silver nitrate 21. CaBr2

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Naming Ionic Compounds

1. sodium carbonate 129.0 g/mol

2. sodium hydroxide 40.00 g/mol

3. magnesium bromide 184.1 g/mol

4. potassium chloride 74.6 g/mol

5. iron (II) chloride 126.8 g/mol

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6. iron (III) chloride 162.3 g/mol

7. zinc hydroxide 99.4 g/mol

8. beryllium sulfate 114.1 g/mol

9. chromium (II) fluoride 90.0 g/mol

10. aluminum sulfide 150 g/mol

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11. lead (II) oxide 223.2 g/mol

12. lithium phosphate 115.7 g/mol

13. titanium (IV) iodide 556.3 g/mol

14. cobalt (II) nitride 204.7 g/mol

15. magnesium phosphide 134.9 g/mol

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16. gallium nitrite 207.7 g/mol

17. silver sulfite 296 g/mol

18. ammonium hydroxide 35.0 g/mol

19. aluminum cyanide 105.0 g/mol

20. beryllium acetate 127.0 g/mol

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Polyatomic Ions

Don’t separate the elements in the ion. Keep them together.

Don’t: N + O3

But NO3-

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Determining the Charge on a Polyatomic Ion

(NO3) - ( N5+ O3

6-)-

(SO4)2- (S6+ O48-)2-

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Determine the oxidation number of the ions in the polyatomic ions below

Phosphate Chlorate Sulfite Permanganate Nitrite Hyroxide

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Oxidation States of Elements in Polyatomic Ions

Phosphate (P5+ O4 8-) 3-

Chlorate (Cl5+ O36-) –

Sulfite (S4+ O3

6- ) 2-

Hydroxide (O2-, H+)-

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Oxidation States of Elements in Polyatomic Ions

Permanganate (Mn 7+ O42-) -

Nitrite (N 5+ O24-) –

Acetate (C26+H3

3-O24-) –

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What are the oxidation states of the atoms below?

Sodium chlorine Magnesium oxygen Barium sulfur Potassium fluoride Aluminum bromine Calcium iodine

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Chlorine

Sulfur

Iodine

Lithium

Chromium (III)

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Chlorine Cl-

Sulfur S2-

Iodine I-

Lithium Li+

Chromium (III) Cr3+

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Iron (III)

Lead (II)

Copper (II)

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Iron (III) Fe3+

Lead (II) Pb2+

Copper (II) Cu2+

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Metallic Elements With Variable Oxidation Numbers

Transition metals, representative metals with p and d sublevels, and the inner transition metals typically have more than one oxidation state in compounds..

Electrons are lost in the following order: p,s,d

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All Other Oxidation Numbers

Assigned so that the sum of the oxidation numbers of each element equals the net charge on the molecule or polyatomic ion.

In neutral compounds, the sum of the positive and negative charge must equal 0.

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Polyatomic Elements

These elements exist as neutral molecules in nature.

Hydrogen, H2 Bromine, Br2

Nitrogen, N2 Iodine, I2

Oxygen, O2 Fluorine, F2

Chlorine, Cl2 Ozone, O3

Phosphorus, P4 Sulfur, S8

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Naming Binary Compounds (Table in Packet)

Sodium & chlorine Magnesium & oxygen Lithium & fluorine Iron & sulfur Copper (II) & chlorine Lead (II) & chlorine Barium & oxygen Calcium & hydrogen

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Naming Binary Compounds (Table in Packet)

NaCl sodium chloride MgO magnesium oxide LiF lithium fluoride FeS iron (II) sulfide CuCl2 copper (II) chloride

PbCl2 iron (II) chloride

AlCl3 aluminum chloride BaO barium oxide CaH2 calcium hydride

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Examples of Metallic Elements with Variable Oxidation Numbers.

Element

ElectronConfiguration

1st Ion Formed

2nd Ion Formed

3rd Ion Formed

Vanadium [Ar]4s23d3V 2+ V 3+ V 4+ & V 5+

Iron [Ar]4s23d6Fe 2+ Fe 3+

Lead

[Xe] 6s24f145d10

6p2Pb 2+ Pb 4+

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Isoelectronic?

These elements are not isoelectronic with a noble gas when the outermost electrons are lost.

That is, they will not have the same number of electrons as the noble gas before it them in the periodic table.

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EXPERIMENT: WATER OF HYDRATION

Purpose: Determine that all the water has been driven from a

hydrate by heating a sample to constant mass. Use experimental data to calculate the moles of

water released by a hydrate Infer the empirical formula of the hydrate from the

formula of the anhydrous compound and experimental data.

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Common Oxidation Numbers for Monatomic Ions

Na + = sodium Cl- = chloride Mg2+ = magnesium S2- = sulfide Ba2+ = barium O2- = oxygen K + = potassium F- = fluoride Al3+ = aluminum Br- = bromide Sr2+ = strontium I- = iodide Ca2+ = calcium

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Introduction

Many ionic compounds, when crystallized from an aqueous solution, will take up definite amounts of water as an integral part of their crystal structure. This water of crystallization may be driven off by heating the hydrated substance to convert it to its anhydrous form.

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SAFETY

Handle the crucible and cover with clean crucible tongs only.

Heat objects can be hot enough to burn even if they look cool.

Always use crucible tongs to handle crucibles and covers.

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Procedures

1. Mass the crucible and cover. Record 2. Add the magnesium sulfate to the crucible. 3. Mass the crucible, cover and magnesium sulfate. Record 4. Place the crucible and cover on the triangle as

demonstrated. 5. Heat slowly for 3 min with the crucible partially covered. 6. Heat strongly for 10 min. 7. Remove crucible, cover and contents and let cool for 5

minutes. 8. Mass the crucible, cover and magnesium sulfate. 9. Heat strongly for 5 minutes. 10. Repeat #7 & 8.

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CLEANUP & DISPOSAL

Clean all apparatus and your lab station. Return equipment to its proper place. Dispose of the magnesium sulfate in the sink.

Flush with water. Wash your hands thoroughly after all work is

finished and before you leave the lab.

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DATA TABLE

1. Mass of empty crucible and cover 2. Mass of crucible, cover and magnesium

sulfate hydrate 3. Mass of crucible, cover and anhydrous

magnesium sulfate after 1st heating 4. Mass of crucible, cover and anhydrous

magnesium sulfate after 2nd heating.

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Fundamentals of ChemistryHomework: P. 114 – 115: 6 - 10

6. How many valence electrons are in an atom of each of the following elements?

A) Ne = 8 E) Na = 1 B) Br = 7 F) As = 5 C) S = 6 G) Sn = 4 D) Sr = 2 H) In = 3

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FC : Question # 7

Classify each of the elements in question 6 as a metal, nonmetal, or metalloid.

A) Ne = nonmetal E) Na = metal B) Br = nonmetal F) As = metalloid C) S = nonmetal G) Sn = metal D) Sr = metal H) In = metal

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FC : Question # 8

Write the electron dot structure for each of the following elements. What is the group number of each element?

A) Cl = 7A or 17 E) Kr = 8A or 18 B) Mg = 2A F) Cs = 1A C) C = 4 A or 14 G) O = 6A or 16 D) Bi = 6A or 15 H) P = 5A or 15

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Lewis Structure

Lewis structure is just the symbol of the element and the number ofelectrons on the outermost energy level.

Example: sodium Na has one electronOn its outermost energy level. Thus Na•

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FC : Question # 9

The electron dot structures of four elements are shown. Without referring to the periodic table, give the family name for each element.

A) iodine = halogen B) barium = alkaline earth metal C) rubidium = alkali metal D) radon = noble gas

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FC : Question # 10

a) Find the synthetic elements on the periodic table.

b) What are the atomic numbers? c) Which synthetic elements are not found with

the others on the periodic table?

B) Elements that are 93 and higher are synthetic elements.

C) Technetium (43) and promethium (61).

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FC: Hwk.: P. 115 ( 11 – 15)

List the elements along with their chemical symbols and atomic numbers that have names similar to the names of planets in the solar system.

Mercury = Hg (80) Uranium = U (92) Neptunium = Np (93) Plutonium = Pu (94)

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12. Rb – Atomic mass (86.1 u) K – density, 1.19 g/ml Cs – melting point, 290 K

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13. Be and Sr F and I

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14. Element (a) (b) (c) (d) hydrogen 1,1 nm g H(1 dot) lithium 2,1 m s Li (1 dot) nitrogen 2,15 nm g N (5 dots) fluorine 2,17 nm g F (7 dots) cobalt 4,9 m s silver 5,11 m s iodine 5,17 nm s I(7dots) mercury 6,12 m l

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15. Americium is radioactive.

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16. Electrical conductivity increases because the outer level electrons are farther from the nucleus and can move more freely

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Naming Ternary CompoundsTable in Packet

Iron (II) sulfite Copper (II) nitrate) Calcium permanganate Silver nitrate Potassium chlorate Magnesium carbonate Lead (II) hydroxide Nickel (II) phosphate Ammonium sulfite

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17. Bromine and mercury are liquids. Mercury is a metal because it has two

valence electrons that are not tightly held.

Bromine is a nonmetal because it has seven valence electrons that are tightly held.

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18. The noble gases are unreactive because they have a filled valence level.

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19. As you move down a column, the atomic number increases and the wavelength of the mitted X ray decreases.

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21. Ni and Zn are corrosion resistant, malleable, and relatively abundant.

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Question For Today

(Put in Cw/Hw Notebook)Ionic or Molecular Compounds?

1. sodium chloride NaCl 2. barium oxide BaO 3. carbon monoxide CO 4. carbon dioxide CO2

5. calcium carbonate CaCO3

6. sulfur dioxide SO2

7. sodium nitrate NaNO3

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Chapter 3