3.3.5 lab

docx

School

Southwestern College, California *

*We aren’t endorsed by this school

Course

333

Subject

Chemistry

Date

Feb 20, 2024

Type

docx

Pages

Uploaded by GrandRam3420

WITH EXTENSION Periodic Properties | Semester 1, Unit 3 1 Copyright © 2017 Quality Science Labs, LLC LAB 3: PERIODIC PROPERTIES NOTE TO STUDENTS: This is a dry lab. You are only expected to perform the portions of this lab that do not require you to use laboratory equipment or supplies. When appropriate, sample data may be supplied in the lab’s data tables to help you answer the questions. Goals 1.Introduce the concept of element groups 2.Show how elements in their groups are similar to one another and explain why Materials and Equipment Slide of elements: Carbon Germanium Silicon Tin Digital voltmeter Goggles Periodic table Materials Not Included Hot water Ice Shallow dish Introduction The periodic table is periodic, which means that it repeats. This happens because atoms fill their outer-shell electron orbits in an organized way. The outer-shell electrons are almost entirely responsible for the chemical properties of the elements. The columns on the periodic table contain elements that have identical outer- shell electrons. These columns are called element groups . Group I (1A) elements are comprised of the alkali metals, which are all very reactive. They form ionic compounds with many elements that are in the group 16 (6A) and group 17 (7A) columns. Other groups have different similarities.

Apex Learning: Chemistry Labs 2 Copyright © 2017 Quality Science Labs, LLC In this lab, we will study the group 14 (4A) elements, which are carbon, silicon, germanium, tin, and lead. We will omit lead from the actual hands-on examination. All the group 14 (4A) elements are commonly seen in ordinary life. Elemental carbon can been seen if you burn your toast or in the pencil “lead.” Silicon is the basis for most electronic microchips in use today. Germanium is less common, but it too is used to make microchips. Tin is used in most solders. Lead is a solder, as well as a weight for fishing and balancing car tires. Many of the group 14 (4A) elements are classified as semiconductors . They are not insulators, since they can pass some current, but they are not conductors since they have a higher resistance than most metals. Semiconductors have an electrical resistance that is sensitive to temperature. You will investigate their changing resistance in this lab. Procedure 1.Using the periodic table, write out the electronic structures of all the group 14 (4A) elements. Record your answers in Table 3.1. 2.Check the room temperature resistance of C , Si , Ge , and Sn . To do this you will put the multimeter on the resistance range in the 200 Ohm scale. Touch the two probes to different ends of each sample provided. Wait until the resistance reading is relatively stable and record an approximate value. The values do move around a bit, so make your best estimate. Record the values in Table 3.2.

Periodic Properties | Semester 1, Unit 3 3 Copyright © 2017 Quality Science Labs, LLC 3.Make some ice water and pour it into a very shallow dish. Place the slide with the sample elements into the ice water and wait a minute for them to cool. Dry the samples and quickly measure the resistance of each sample. Again, you will need to wait for the resistance value to stabilize and then make your best estimate of the value. Record your results in Table 3.2. 4.Repeat the test again, using hot water in the shallow dish instead of cold water. You will need to preheat the dish with hot water to make sure the water remains as hot as possible. 5.Take a knife or small screwdriver and attempt to make a very small scratch on the element samples. If you have access to a lead wheel weight or a lead fishing weight, you may examine that and add the results to the Table. Try to determine if the samples tend to be hard and brittle, or soft and ductile. Fill out Column 3 in Table 3.1.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

Periodic Properties 3 Copyright © 2017 Quality Science Labs, LLC LAB 3 Questions for Periodic Properties Table 3.1 Element Electronic Structure Brittle/Ductile/in Between Carbon Brittle but can be hard or strong depending on the atomic structure Silicon Brittle Germanium Brittle Tin Ductile, but hardens rapidly Lead Very ductile Table 3.2 Element Resistance, in Ice Water Resistance, Room Temperature Resistance, in Hot Water Carbon Higher 1 kΩ Lower Silicon Higher 192 kΩ Lower Germanium Higher 46 kΩ Lower Tin Low, but likely not to change much with temperature change Low, but not likely to change much with temperature change Low, but likely not to change much with temperature change 1.In what ways are the electronic structures of the group 14 (4A) elements similar? In what ways are they different?

Apex Learning: Chemistry Labs 4 Copyright © 2017 Quality Science Labs, LLC 2.Compare the room temperate resistances for all the samples. Are they similar or different? The room temperature resistance should be much less for tin and lead. They behave like metals, and so have lower resistance. 3.How does resistance change with temperature? Is there more resistance or less resistance at higher temperatures? Compare the change in resistance for all the samples. 4.Are the samples soft and ductile or hard and brittle? Are some in between? 5.What do you think causes the difference between the elements on the top of the periodic table, like carbon, with those on the bottom of the periodic table, like tin or lead?