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עמוד:25
Chemical Families Elements that are in the same column of the periodic table are called a chemical group . In the following experiments we will test the properties of elements belonging to one of the chemical groups – the alkali metals . Activity A Demonstration Experiment The properties of the group of alkali metals Purpose : to learn about the properties of the alkali metals sodium and potassium . Protective gear : safety goggles , fume closet . Equipment : safety goggles , a jar containing lumps of sodium immersed in kerosene , a 250 ml beaker containing 150 ml of water , tweezers , knife . Activity : A . Find the elements sodium and potassium in the periodic table . Where are they located ? B . The sodium is in a jar , covered with kerosene . Look at it and describe its appearance . C . A small piece of the sodium is cut with a knife . Is the metal soft – does it cut easily ? Observe the area of the cut : what color is it ? Is it shiny ? D . After making the cut , the piece of sodium is removed from the kerosene using the tweezers , and placed in beaker containing water . Describe what happens . Hypothesize : What will happen in a similar experiment with potassium ? Explain . E . Find and watch an Internet clip from the Internet describing a similar experiment with potassium . Were you right in your hypothesis regarding the potassium experiment ? Results : Organize the results of your observations and experiment in a table . Give the table an appropriate title . Summary and conclusions : 1 . What was similar and what was different in the properties of the potassium and the sodium ? 2 . Scientists performed the same experiment with the metal rubidium . Hypothesize : What will the results of the activity be ? Explain .
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