Independent Unit Part 3 + Unit Review Name________________________

Ionic Compounds Activity

The Model: Cations vs. Anions

1. Notice the shape and charge of the cation model. Why do you think there are slots in the cations? (Hint: How

did the atoms become ions?)

2. Notice the shape and charge of the anion model. Why do you think there are tabs in the anions? (Hint: how did the atoms become ions)?

3. Similarly, a 2+ cation would look like this: Draw a 2- anion:

4. If you were to make a neutral compound using a cation and anion following the model, what would the shape be of the neutral compound be?

5. Group the ion models by family. What do you notice about the number of tabs or slots? What do you notice about the tabs or slots and charge of all ions? Is there a pattern?

Bonding and Predicting Chemical Formulas

Al2O3

2Aluminum ions 3 Oxide ions

Fill in the blanks below with these words: subscripts, compound, ions, charge, number, ratio, formula, balance,

zero

The ______________ show the ___________ of each atom in the ________________.

For an ionic bond, the charges of the _______ need to add up to _____________. The chemical ___________

shows how many of each ion is needed to _____________ the ____________ and make the compound neutral.

The __________ of the ions should be in lowest terms.

Activity

Obtain a bag of ions from the instructor and create the bonds listed. Complete the table below and make the

compounds from the following list. The first one is completed for you as an example.

Elements Ion name Ion symbol

with charge

Anion/Cation How many? Chemical

Formula

EXAMPLE

Potassium &

Chlorine

Potassium K+1 Cation 1

KCl Chlorine Cl-1 Anion 1

Lithium and

oxygen

Sodium and

fluorine

Titanium (IV)

and oxygen

Iron (II) and

oxygen

Iron (III) and

oxygen

Yttrium (III)

and chlorine

Calcium and

nitrate

Copper (I) and

phosphide

Magnesium and

nitride

Copper (II) and

phosphide

Aluminum and

bromine

Silver and

iodine

Types of Bonds Activity Purpose: To determine the properties of Metals, Ionic Compounds and Covalent Molecules. Materials: Electronic Apparatus, metal strip, cup of salt, cup of sugar, and a cup with water Procedures & Data Table: Follow the directions and check “yes” or “no” after completing each step. Procedure Yes No 1. Obtain a piece of metal and place the two wires on the metal. Does the bulb

light up?

2. Place the metal into one of the cups of water. Does the metal dissolve in the water?

3. Clean and dry the metal strip so that it may be used in the future. 4. Obtain a cup with solid ionic salt and place the two wires into the solid salt.

Does the bulb light up?

5. Obtain a cup with water and place the two wires into the water. Does the bulb light up?

6. Pour ½ of the ionic salt into the cup with water and stir. Does the salt dissolved in water?

7. Place the two wires into the cup containing the dissolved ionic salt. Does the bulb light up?

8. Pour the salt solution down the drain and replace the water in the cup. 9. Obtain a cup with solid covalent molecule (sugar) and place the two wires into

the solid sugar. Does the bulb light up?

10. Obtain a cup with water and place the two wires into the water. Does the bulb light up?

11. Pour ½ of the covalent molecule (sugar) into the cup with water and stir. Does the sugar dissolved in water?

12. Place the two wires into the cup containing the dissolved sugar. Does the bulb light up?

13. Pour the sugar solution down the drain and replace the water in the cup.

Summary Table: Metal Ionic Salt Covalent Molecule

(sugar) Dissolves in water?

Metal Solid Ionic

Salt Dissolved Ionic Salt

Solid Covalent Molecule

Dissolved Covalent molecule

Conducts electricity?

Questions:

1. Steps 5 and 10 asks you whether the water conducts electricity. What is the purpose of testing just the water?

2. Does the metal dissolve in water? Why or why not? Explain.

3. When the ionic salt dissolves in water, does the solution conduct electricity? Explain why or why not.

4. When the covalent sugar dissolves in water, does the solution conduct electricity? Explain why or why not.

Metallic Bonding: The kind of bonds holds atoms of metals (i.e. copper, silver, gold) together

Metals tend to lose their valence electrons to obtain a noble gas electron configuration

In a metallic solid, each atom will try to give their valence electron(s) to neighboring atoms

There is a constant movement of electrons (aka “sea of mobile electrons”) throughout the

entire metallic solid since none of the atoms “wants” the electrons

o Think of it as a big game of “Hot Potato”

o The constant movement of valence electrons is what makes solid metals good

conductors of electricity

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Summary Chart

Fill in the following table regarding the differences between the types of compounds you’ve learned about so far this unit.

Ionic Compounds Covalent (Molecular) Compounds

Metals

Made up of… (metal, nonmetal)

Electrons are…. (transferred, shared, constantly moving)

Physical Properties: (high vs low BP/MP…does or does not conduct)

________ melting point & boiling point

Solids ______________ conduct electricity

When dissolved in water: _______ conduct electricity

________ melting point & boiling point

Solids _____________ conduct electricity

When dissolved in water: _____ conduct electricity

_______ melting point & boiling point

Solids _____ conduct electricity

Cu Cu

Cu Cu

Read the comic strip “The Bare Essentials of Polarity,” and use it to answer these questions.

1. How does the comic strip define a polar molecule? What causes polarity?

2. What is electronegativity?

3. How does electronegativity change depending based on an element’s location on the

periodic table?

4. What is the artist trying to represent by two polar bears arm wrestling or two penguins arm

wrestling?

5. What three types of bonds are represented on the third page of the comic strip? Describe the

characteristics for the 3 different bonds.

***We can classify a bond as ionic or covalent in one of two ways:

1) Look at the type of elements bonded together

a. METAL and a NONMETAL=_____________________________

b. NONMETAL and a NONMETAL=_________________________

2) Look at the electronegativity difference between the 2 bonded elements

a. 0 - 0.3 ________________________________________________

b. 0.4 - 1.7 ________________________________________________

c. > 1.7 _________________________________________________

Practice:

1. Identify the elements in each compound as a metal or nonmetal. Compound Electronegativity

difference between bonded elements

Ionic, Nonpolar Covalent, or Polar Covalent?

H2O 3.5 − 2.1 = �. � Polar Covalent

Na2O

N2O6

CH4

KCl

HCl

CBr4

H2

CO2

Na2S

CH4

O2

2. What types of molecules will always have a nonpolar bond between them?

a. Diatomic element **How do you know?

b. Ionic compound

c. Covalent compound

d. Metallic element

3. What is the difference between a polar and a nonpolar covalent bond? Explain your answer

in terms of both electronegativity difference and how the electrons are shared.

Element Electroneg

F 4.0

O 3.5

Cl 3.0

N 3.0

Br 2.8

C 2.5

S 2.5

H 2.1

Na 0.9

K 0.8

UNIT 9 PRACTICE TEST Name Multiple Choice Questions 1. Ionic bonds are normally formed when A. electrons are shared between a metal and a

nonmetal B. electrons are shared between two nonmetals C. electrons are transferred from a metal to a

nonmetal D. electrons are transferred from a nonmetal to

a metal 2. Covalent bonds are normally formed when A. electrons are shared between a metal and a

nonmetal B. electrons are shared between two nonmetals C. electrons are transferred from a metal to a

nonmetal D. electrons are transferred from a nonmetal to

a metal 3. Which of these compounds is classified as IONIC? A. CO2 B. SF2 C. ZnCl2 D. SeBr2 4. Which of these compounds is classified as COVALENT? A. PF3 B. GaCl3 C. NiBr3 D. CrO3 5. Which of these compounds requires a Roman numeral in its name? A. SF6 B. ZnO C. AlBr3 D. PdCl2 6. The correct formula for strontium phosphide is A. Sr2P3 B. Sr3P2 C. SrPO4 D. Sr3(PO4)2 7. The correct formula for aluminum sulfide is

A. Al2S3 B. Al3S2 C. AlSO4 D. Al2(SO4)3

8. The correct formula for calcium hydroxide is A. CaO B. CaH2 C. CaOH2 D. Ca(OH)2 9. The correct name for Na3N is A. sodium nitride B. trisodium mononitride C. sodium(III) nitride D. sodium nitrate 10. The correct name for CaCl2 is A. calcium(II) chloride

B. calcium chloride C. calcium dichloride D. calcium chlorate 11. The correct formula for sodium carbonate is A. Na4C B. NaCO3 C. Na2CO3 D. Na3CO3 12. The correct name for Mg(NO3)2 is A. magnesium nitride B. magnesium nitrate C. magnesium dinitrate D. magnesium(II) nitrate 13. The correct name for CuCrO4 is A. copper chromate B. copper(II) chromate C. copper chromate(II) D. copper chromium tetroxide 14. The correct formula for dinitrogen trioxide is A. N2O B. N2O3 C. N2O4 D. N3O2 15. The correct name for SF4 is A. sulfur(IV) fluoride B. sulfur fluoride(IV) C. sulfur trifluoride D. sulfur tetrafluoride

Short Answer Questions 1. Calculate the percent composition of caffeine, C8H10N4O2. Show work! % carbon % hydrogen % nitrogen % oxygen 2. Fill in the empirical formulas for each covalent compound below.

Molecular Formula

Empirical Formula

Molecular Formula

Empirical Formula

C16H12O4 C14H20O2

Na2S4O6 K2C4H4O6

3. How many grams are in 5.66 moles of calcium carbonate?

4. A sample of sodium sulfate has a mass of 14.5 g. Calculate the number of sodium sulfate molecules present in the sample.

5. A substance with an empirical formula of CH2 has a molar mass of 84.18 g/mol. What is the molecular formula of this compound?

6. A substance with an empirical formula of CF3 has a molar mass of 138.02 g/mol. Determine the molecular formula of the compound and its name.

7. Decide if the description represents IONIC bonding or COVALENT bonding It is a non-conductor of electricity, whether it exists as a solid, melted, or dissolved in water.

It is a nonelectrolyte in the solid form, but it can become a good conductor when melted or dissolved in water. The building blocks of this type of compound are called molecules. The electrons are transferred from one element to another to form this type of bond. The electrons are shared in between elements in this type of bond. 8. Rank from ionic, covalent and metallic from strongest to weakest strength between

molecules (think: which has the highest boiling point; higher boiling point = stronger)

NAMING COMPOUNDS & WRITING CHEMICAL FORMULAS PRACTICE I. Simple Binary Ionic Compounds:

1. MgCl2 1. Lithium oxide

2. NaI 2. Barium fluoride

3. Na2S 3. Cesium sulfide

4. Cs2Se 4. Beryllium oxide

5. Al2S3 5. Strontium iodide

II. Binary Ionic Compounds with Multi-Valent Metals:

1. FeCl3 1. Chromium (IV) sulfide

2. SnS2 2. Cobalt (II) bromide

3. Ti2O3 3. Nickel (III) phosphide

4. PbF2 4. Gold (I) nitride

5. PtSe2 5. Iron (II) arsenide

III. Ionic Compounds with Polyatomic Ions:

1. NaCH3COO 1. Silver nitrite

2. ZnCO3 2. Ammonium hydroxide

3. Al(NO3)3 3. Magnesium Phosphite

4. KNO3 4. Lead (IV) nitrate

5. Zn3(PO4)2 5. Iron (III) carbonate

IV. Covalent Compounds:

1. SF6 1. Nitrogen monoxide

2. P2O5 2. Carbon dioxide

3. SiO4 3. Bromine trioxide

4. NO2 4. Xenon hexafluoride

5. H2O 5. Difluorine disulfide

V. Acids:

1. H2CO3 1. Hydrobromic acid

2. HClO2 2. Acetic acid

3. HF 3. Oxalic acid

4. H3PO4 4. Bromous acid

5. HIO4 5. Hydrosulfuric acid