EXPERIMENT 5. The Periodic Table INTRODUCTION

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1 EXPERIMENT 5 The Periodic Table INTRODUCTION The modern periodic law states that when the chemical elements are arranged in order of increasing atomic number, chemical and physical properties repeat periodically A horizontal row on the Periodic Table in called a period or series, and contains elements whose properties vary widely A column on the Periodic Table is called a group or family, and contains elements with similar properties In this experiment you will observe the physical and chemical properties of various elements ranging across the Periodic Table, and attempt to deduce trends in these properties PROCEDURE 1 Students will work individually for this experiment Except for the laboratory handout, remove all books, purses, and such items from the laboratory bench top, and placed them in the storage area by the front door For laboratory experiments you should be wearing closed-toe shoes Tie back long hair, and do not wear long, dangling jewelry or clothes with loose and baggy sleeves Open you lab locker Put on your safety goggles, your lab coat, and gloves PART A - PHYSICAL PROPERTIES OF ELEMENTS 2 Observe the physical properties of the third period elements on display at each lab table, and record these observations in your Data Table After observing the crystals of sulfur, perform the following procedure to prepare a different allotropic form of sulfur 3 Position the snorkel hood so that it is about 15 inches above the lab bench Do so by loosening the three knobs and then adjusting the snorkel hood until it is in the position you want Open the flow valve by turning it until it is parallel with the tubing, indicating that the vacuum is on 47

2 4 Place your burner under the snorkel hood at your lab station Pour about 100 ml of deionized water into a 250-mL beaker and also place it under the snorkel hood at your lab station Obtain a deflagrating spoon from the back of the lab room and half fill it with elemental sulfur 5 Light your burner and heat the sulfur with the burner flame, as shown below, until the sulfur melts CAUTION: Sulfur burns with a pale blue flame, which is hard to see and can cause severe burns Quickly pour the melted sulfur into the beaker of water, and then place the deflagrating spoon in the beaker of water to insure that any burning sulfur is extinguished Remove the sulfur from the beaker Observe the physical properties of the new allotropic form of sulfur, and record these observations in your Data Table along with the observations of the original crystalline sulfur 6 The sulfur may be disposed of in the trash can Clean the deflagrating spoon by placing it back into the burner flame to ignite the residual black sulfur Allow all of the sulfur to burn away, then place the deflagrating spoon in the beaker of water again to cool it off Once cool, return it to the back counter of the lab room 7 Observe the physical properties of the transition elements on display at each lab table, and record these observations in your Data Table 8 Observe the physical properties of the halogens on display in Fume Hood B, and record these observations in your Data Table 48

3 PART B - ACTIVITIES OF METALS 9 Demonstration Observe as a small piece of sodium metal is added to a beaker of deionized water If a change is seen, record R in your Data Table for Reaction, and describe the change If no change is observed, record NR in your Data Table for No Reaction 10 Half-fill 3 medium test tubes with deionized water To the first test tube add one small piece of magnesium metal, to the second test tube add one small piece of iron metal, and to the third test tube add one small piece of copper metal Observe the test tubes for 5 minutes Ignore any color change in the solution because that would be due to an oxide coating reacting with the water If any other change is seen, record R in your Data Table for Reaction, and describe the change If no change is observed, record NR in your Data Table for No Reaction Pour out the water in the sink, but save the pieces of metal for step Place 3 ml of 6 M HCl in 3 medium test tubes CAUTION: Hydrochloric acid is corrosive and can cause severe burns As in step 10, add one small piece of each of the metals to the 3 medium test tubes Observe the test tubes for 5 minutes Ignore any color change in the solution because that would be due to an oxide coating reacting with the acid If any other change is seen, record R in your Data Table for Reaction, and describe the change If no change is observed, record NR in your Data Table for No Reaction 12 Dispose of all liquids from Part B down the sink Metals from Part B may be deposed of in the trash can PART C - ACTIVITIES OF NONMETALS 13 Add 2 ml of chlorine water and 1 ml of heptane each to 2 medium test tubes Set a vortex mixer to auto and to a speed setting of 6 Press one of the test tube into the rubber cup, allowing the contents of the test tube to be mixed for 30 seconds, as shown below Do the same for the other test tube Record the color of the chlorine in the heptane layer CAUTION: Avoid breathing the halogen vapors, and do not use your finger to stopper the tube since a halogen can give you a bad chemical burn 49

4 14 To the first test tube add 4 ml of 01 M sodium bromide, to the second test tube add 4 ml of 01 M sodium iodide, and mix each in the vortex mixer for 30 seconds Record in your Data Table the color in the heptane layer and look for any change in color If the heptane layer underwent a change, record R in your Data Table for Reaction, and describe the change If the heptane layer underwent no change, record NR in your Data Table for No Reaction Save all liquids from Part C in a beaker on your lab bench 15 Add 2 ml of bromine water and 1 ml of heptane each to 2 medium test tubes, and mix them for 30 seconds each Record the color of the bromine in the heptane layer 16 To the first test tube add 4 ml of 01 M sodium chloride, to the second test tube add 4 ml of 01 M sodium iodide, and mix each for 30 seconds Record in your Data Table the color in the heptane layer and look for any change in color If the heptane layer underwent a change, record R in your Data Table for Reaction, and describe the change If the heptane layer underwent no change, record NR in your Data Table for No Reaction Save all liquids from Part C in a beaker on your lab bench 17 Add 2 ml of iodine water and 1 ml of heptane each to 2 medium test tubes, and mix them for 30 seconds each Record the color of the iodine in the heptane layer 18 To the first test tube add 4 ml of 01 M sodium chloride, to the second test tube add 4 ml of 01 M sodium bromide, and mix each for 30 seconds Record in your Data Table the color in the heptane layer and look for any change in color If the heptane layer underwent a change, record R in your Data Table for Reaction, and describe the change If the heptane layer underwent no change, record NR in your Data Table for No Reaction Save all liquids from Part C in a beaker on your lab bench 19 Dispose of all liquids from Part C in the waste bottle in the Fume Hood A 20 Clean and wipe dry your laboratory work area and all apparatus When you have completed your lab report have the instructor inspect your working area Once your working area has been checked your lab report can then be turned in to the instructor 50

5 EXPERIMENT 5 LAB REPORT Name: Student Lab Score: Date/Lab Start Time: _ Lab Station Number: DATA TABLE PART 1 Period 3 Elements Physical State Physical Properties Metal/Nonmetal Sodium Magnesium Aluminum Silicon Phosphorus Sulfur Chlorine Argon 51

6 PART 1 Transition Elements Physical State Physical Properties Metal/Nonmetal Iron Copper Zinc PART 1 Halogens Physical State Physical Properties Metal/Nonmetal Chlorine Bromine Iodine 52

7 PART 2 Metal Activity With Water (R or NR) With 6 M HCl (R or NR) Sodium Magnesium Iron Copper PART 3 Nonmetal Activity Halogen's Color in Heptane Layer With 01 M NaCl (R or NR) With 01 M NaBr (R or NR) With 01 M NaI (R or NR) Chlorine Bromine Iodine 53

8 QUESTIONS 1 Identify an element, other than those you have observed in this experiment that would fit each description given below silvery, soft, solid, extremely active metal silvery, medium-soft, solid, very active metal silvery, solid, very hard metal silvery, solid, very inactive metal silvery, liquid, very inactive metal silvery, solid, radioactive metal very active, colorless gas inert, colorless gas 2 Of the elements you observed in Part 1 of the experiment, which one element should most likely be classified as a metalloid? 3 What is similar about the electronic configurations of metal atoms? 4 What change do metal atoms undergo when they react? 5 From your results in Part 2, arrange the metals sodium, magnesium, iron, and copper in order of decreasing activity Most active Least active 6 Which metal in question 5 would most likely be found naturally in its elemental form on Earth? 54

9 7 What is similar about the electronic configurations of nonmetal atoms? 8 What change do nonmetal atoms undergo when they react? 9 From your results in Part 3, arrange the nonmetals chlorine, bromine and iodine in order of decreasing activity Most active Least active 10 Give the most likely ionic charge for ions of each of the following representative elements: Sodium Magnesium Aluminum Silicon Phosphorus Sulfur Chlorine 11 Give the 2 most likely ionic charges for ions of the following element: Thallium (Tl) 55

10 12 Using the periodic table below: (a) indicate the element with the largest atomic radius by placing an L in its position (b) indicate the element with the smallest atomic radius by placing an S in its position (c) draw an arrow from the element with the smallest atomic radius to the element with the largest atomic radius to show the trend in increasing atomic radii across the periodic table 13 Using the periodic table below: (a) indicate the element with the largest first ionization energy by placing an L in its position (b) indicate the element with the smallest first ionization energy by placing an S in its position (c) draw an arrow from the element with the smallest first ionization energy to the element with the largest first ionization energy to show the trend in increasing first ionization energies across the periodic table (d) darken in any columns on the periodic table that would be exceptions to first ionization energy trend 14 Using the periodic table below: (a) indicate the element with the most exothermic electron affinity by placing an X in its position (b) draw an arrow to show the trend in increasing exothermic electron affinities across the periodic table (c) darken in any columns on the periodic table that would be exceptions to electron affinity trend 56