Unit 3 Bonding Study Guide

Unit 3 Bonding Study Guide Chemistry Standard Set 2

Key Vocabulary Terms 1. Ionic Bond 9. Non-metal 2. Covalent Bond 10. Neutrality 3. Metallic Bond 11. Electrostatic Attraction 4. Oxidation State 12. Cation 5. Coefficient 13. Anion 6. Subscript 14. Shared Pairs 7. Superscript 15. Unshared Pairs 8. Metal 16. Outer Electrons/Valence Electron

Concepts 1. Orbitals 2. Energy – energy to form bonds, bond energy 3. Crystal Lattice – Alternating positive and negative ions to form ionic solids 4. Properties of Covalent, Ionic, and Metallic Compounds Covalent – non-metals, lower melting points, non-conductor of electricity Ionic – metals and non-metals, higher melting points, conductor of electricity Metallic – metals, conductor of electricity and heat, malleability, ductility, reacts with acid 5. Neutrality in atoms and in the formation of formulas 6. Nomenclature- primarily ionic and some covalent (e.g., mono, di , and tri) 7. Formation 8. Dissolving

Items for Memorization Polyatomic Ions Diatomic Molecules Transition Metal Oxidation -1 Nitrate ion NO3 Hydrogen H2 States -2 Sulfate ion SO4 Nitrogen N2 Iron Fe II and III +1 Ammonium ion NH4 Chlorine Cl2 Copper Cu I and II -3 Phosphate ion PO4 Iodine I2 Zinc Zn II -1 Hydroxide ion OH Bromine Br2 Gold Au I and III -2 Carbonate ion CO3 Fluorine F2 Mercury Hg I and II Oxygen O2 Lead Pb II and I

Skills 1. Ability to draw Lewis Dot Structures Atoms (e.g., Na, Ba, Al, C, N, O, Cl, and Ne) Covalent Compound (e.g., N2, O2, Cl2, and H2) Polyatomic Structure (e.g., H2O, CO2, and CH4)

2. Ability to inventory compounds: Number and Type of Atoms (e.g., Al2(CO3)3, ( NH4)3PO4, and Ba(OH)2)

3. Ability to name ionic compounds given the formula and write the formula given a name (e.g., magnesium bromide, calcium hydroxide, iron III sulfate, and gold I phosphate)

4. Ability to predict bond types (e.i., ionic, covalent, and metallic) Name: The Alkaline Earth Elements Date: Class: Background Information The arrangement of the elements in the periodic table is one of the most important achievements in modern chemistry. The physical and chemical properties of elements change in a regular pattern as you go both across the rows and down the columns of the periodic table. As a result, when elements close to each other in a row or column are compared, they have many of the same properties. However, when elements farther away from each other in a row or column are compared, they have more dissimilar properties.

The elements in Group 2 of the periodic table are known as the alkaline earth elements. Like all members of a group, or family, of elements, they have certain properties that change in a regular pattern within the group. One of these properties is the ability to form a precipitate, or solid substance, as a result of a chemical reaction. The precipitate cannot dissolve in water and eventually settles to the bottom of the container. In this investigation, you will compare the abilities of the alkaline earth elements to form precipitates as a result of a chemical reaction.

Question: Will the ability of the alkaline earth elements to form precipitates increase or decrease as you move from top to bottom?

Hypothesis:

Materials (per group) o Safety goggles o Dropper bottles of: o Spot plate . magnesium nitrate . calcium nitrate o Sheet of notebook paper . strontium nitrate . barium nitrate . potassium carbonate . potassium sulfate . potassium chromate

Procedure 1. Place the spot plate in the center of a sheet of notebook paper so that there are 4 spots running down and 3 spots running across. See Figure 1. 2. Along the side of the notebook paper next to each of the four spots, write the names of the four alkaline earth elements that are present in each nitrate compound listed in the materials you are using. Write them in the same order in which they are listed. See Fig- ure 1. 3. Along the top of the notebook paper next to each of the three spots, write the names of the three substances that are combined with potassium in the materials you are using. See Figure 1. 4. Put on your safety goggles. Place 3 drops of potassium carbonate in each of the four spots under the word "carbonate." Place 3 drops of potassium sulfate in each of the four spots under the word "sulfate." Place potassium chromate in each of the four spots under the word "chromate." Be very careful not to mix the liquid from one spot with the liquid from another. 5. "Shake the dropper bottle of magnesium nitrate and place 3 drops in each of the three spots in the row labeled "magnesium." Observe each spot carefully and record the result in the Data Table. Repeat this procedure using the dropper bottles containing calcium nitrate, strontium nitrate, and barium nitrate. Be very careful not to mix the liquid from one spot with the liquid from another. 6. After recording your results, wash your spot plate thoroughly with soapy water and a brush.

Observations

DATA TABLE (2 points) (Use ppt for a precipitate and NR for no reaction.) Alkaline earth Carbonate Sulfate Chromate Metal

Magnesium

Calcium

Strontium

Barium

Conclusion: (8 points) (In the form of a paragraph.) 1. Restate your hypothesis. 2. Was your hypothesis supported or denied? Explain. 3. Was there evidence of a chemical reaction occurring in any of the spots? Explain your answer. 4. Which alkaline earth element formed the smallest number of precipitates? 5. Which alkaline earth element formed the greatest number of precipitates? 6. What is the relationship between the number of precipitates formed and the location of the alkaline earth element on the periodic table? 7. If the ability of an alkaline earth element to form a precipitate is an indication of its ability to chemically react with other substances, which is the most reactive element? The least reactive? 8. List the alkaline earth metals in order of their chemical reactivity, starting with the most reactive. 9. How does the order of the elements you listed in question 8 compare to their order in the periodic table?

Application and Critical Thinking (4 points) (Answer question below.) 1. Group 1 in the periodic table is known as the alkali metals. Based on your investigation of' the Group 2 elements, predict the comparative reactivity of the elements in Group 1 of the periodic table. 2. If you had a solution containing a mixture of magnesium, strontium, and barium, how could you separate the three elements (Hint: Review the information in the Data Ta- ble.)