Name: ______Periodic Trends Activity Many properties of the elements change in a predictable way as you move through the periodic table. These variations are called periodic trends. In this activity, you will be making a model of four of the periodic trends. A model is an idea, system, or structure that represents what you are trying to explain. Models are especially useful when trying to visual something to large or too small to be seen. At the end of the activity, you will examine all of the models of the trends and answer a series of questions.
Materials Styrofoam sheet scissors ruler glue stick trend tables straws marker tape golf pencil glue bottle
Atomic Radius Atomic radius is approximately the distance from the nucleus of an atom to the outside of the electron cloud where the valence electrons are found. The radius of the atom depends on how many valence electrons are present and it depends on their distance form the attractive force of nucleus.
Procedure 1. Turn the Styrofoam horizontally. a. Use a glue stick to glue the Atomic Radius Table to the top left corner. b. Glue the Ionic Radius Table to the top right corner. c. Glue the Ionization Table to the bottom left corner. d. Glue the Electronegativity Table to the bottom right corner. 2. In the table below are the atomic radii for the representative group elements expressed in picometers. To convert these into a measurement you can use in your model, you use a conversion factor of 40 pm = 1 cm. Essentially, all you do is divide each ionic radius by 40 and express your answer in centimeters with only 1 digit past the decimal. Then add 0.5 cm. As you convert the atomic radii into cm, you should write the measurements in the appropriate space on the lab sheet (pages 2-4). Once you have made all your conversions let your teacher know and you may get your materials. 3. Using the ruler, marker, and the scissors cut a straw to the lengths in centimeter measurements on your chart. 4. Use a golf pencil to make a hole in the location of that element (your teacher will show you how). 5. Put a little bit of glue into the hold. 6. Put in the corresponding hole in the Styrofoam. 7. Repeat this for all elements listed.
Ionic Radius Atoms can gain or lose electrons to form ions. Because electrons are negatively charged, atoms that gain or lose electrons acquire a net charge. Thus, an ion is an atom that has a positive or negative charge. When atoms lose electrons to form a positive ion they always become smaller. When atoms gain electrons to form a negative ion, they always become larger.
Procedure 1. Repeat steps 2-7 for Atomic Radius. Ionization energy Ionization energy is the energy needed to overcome the attraction between the positive charge of the nucleus and the negative charges of the electrons and remove electrons from an atom. Think of ionization energy as how strongly an atom’s nucleus holds onto its valence electrons. A high ionization energy value indicates that an atom has a strong hold on its valence electrons and is less likely to lose its electrons. A low ionization energy indicates that an atom has a weak hold on its valence electrons and is likely to lose one or more electrons.
Procedure 1. Repeat steps 2-7 for atomic radius. However, you now divide each energy value by 200 and express your answer in centimeters with only 1 digit past the decimal. Then add 0.5 cm. This is because the conversion factor is now 200 KJ/mol = 1cm. As you convert the energies into cm, you should write the measurements in the appropriate space on the diagram. Once you have made all your conversions let your teacher know and you will be given the straws.
Electronegativity The electronegativity of an element indicates the relative ability of its atoms to attract electrons in a chemical bond. These values are calculated on a number of factors and are expressed in terms of a numerical value of 4.0 or less. The units used to express electronegativities are called Paulings.
Procedure 1. Repeat steps 2-7 for atomic radius. However, you now multiply each value by 2 and express your answer in centimeters with only 1 digit past the decimal. Then add 0.5 cm. This is because the conversion factor is now 2 Paulings = 1cm. As you convert the energies into cm, you should write the measurements in the appropriate space on the diagram. Once you have made all your conversions let your teacher know and you will be given the straws.
H Atomic Radius He 37 31 ____ (in picometers) Li Be B C N O F Ne 152 112 85 77 75 73 72 71 ___ Na Mg Al Si P S Cl Ar 186 160 143 118 110 103 100 98 ____ K Ca Ga Ge As Se Br Kr 227 197 135 122 120 119 114 112 ____ Rb Sr In Sn Sb Te I Xe 248 215 167 140 140 142 133 131 ______Cs Ba Tl Pb Bi Po At Rn 265 222 170 146 150 168 140 140 ______Fr Ra 280 228 ______
H Ionic Radius He -- (in picometers) -- Li Be B C N O F Ne 76 31 20 15 146 140 133 -- Na Mg Al Si P S Cl Ar 102 72 54 41 212 184 181 -- K Ca Ga Ge As Se Br Kr 138 100 62 53 222 198 195 -- Rb Sr In Sn Sb Te I Xe 152 118 81 71 62 221 220 -- Cs Ba Tl Pb Bi Po At Rn 167 135 95 84 74 ------Fr Ra -- --
H Electronegativity He 2.2 (in Paulings) -- Li Be B C N O F Ne 1.0 1.6 2.0 2.6 3.0 3.4 4.0 -- Na Mg Al Si P S Cl Ar 0.9 1.3 1.6 1.9 2.1 2.5 3.2 -- K Ca Ga Ge As Se Br Kr 0.8 1.0 1.8 2.0 2.2 2.6 3.0 -- Rb Sr In Sn Sb Te I Xe 0.8 1.0 1.8 2.0 2.1 2.1 2.7 -- Cs Ba Tl Pb Bi Po At Rn 0.8 0.9 1.8 1.9 1.9 2.0 2.2 -- Fr Ra 0.7 0.9
H Ionization Energy He 1312 (in KJ/mole) 2372
Li Be B C N O F Ne 520 900 801 1087 1402 1314 1681 2081
Na Mg Al Si P S Cl Ar 496 738 578 787 1012 1000 1256 1521
K Ca Ga Ge As Se Br Kr 419 590 579 761 947 941 1140 1351
Rb Sr In Sn Sb Te I Xe 403 550 558 708 834 869 1008 1170
Cs Ba Tl Pb Bi Po At Rn 376 503 589 716 703 813 916 1037
Fr Ra 393 509
H Atomic Radius He 37 (in picometers) 31 Li Be B C N O F Ne 152 112 85 77 75 73 72 71
Na Mg Al Si P S Cl Ar 186 160 143 118 110 103 100 98 K Ca Ga Ge As Se Br Kr 227 197 135 122 120 119 114 112
Rb Sr In Sn Sb Te I Xe 248 215 167 140 140 142 133 131
Cs Ba Tl Pb Bi Po At Rn 265 222 170 146 150 168 140 140 Fr Ra 280 228
H Ionic Radius He -- (in picometers) -- Li Be B C N O F Ne 76 31 20 15 146 140 133 -- Na Mg Al Si P S Cl Ar 102 72 54 41 212 184 181 -- K Ca Ga Ge As Se Br Kr 138 100 62 53 222 198 195 -- Rb Sr In Sn Sb Te I Xe 152 118 81 71 62 221 220 -- Cs Ba Tl Pb Bi Po At Rn 167 135 95 84 74 ------Fr Ra -- --
H Electronegativity He 2.2 (in Paulings) -- Li Be B C N O F Ne 1.0 1.6 2.0 2.6 3.0 3.4 4.0 --
Na Mg Al Si P S Cl Ar 0.9 1.3 1.6 1.9 2.1 2.5 3.2 -- K Ca Ga Ge As Se Br Kr 0.8 1.0 1.8 2.0 2.2 2.6 3.0 --
Rb Sr In Sn Sb Te I Xe 0.8 1.0 1.8 2.0 2.1 2.1 2.7 --
Cs Ba Tl Pb Bi Po At Rn 0.8 0.9 1.8 1.9 1.9 2.0 2.2 -- Fr Ra 0.7 0.90
Ionization Energy H He 1312 (in KJ/mole) 2372
Li Be B C N O F Ne 520 900 801 1087 1402 1314 1681 2081
Na Mg Al Si P S Cl Ar 496 738 578 787 1012 1000 1256 1521
K Ca Ga Ge As Se Br Kr 419 590 579 761 947 941 1140 1351
Rb Sr In Sn Sb Te I Xe 403 550 558 708 834 869 1008 1170
Cs Ba Tl Pb Bi Po At Rn 376 503 589 716 703 813 916 1037 Fr Ra 393 509
Ionization Energy H He 1312 (in KJ/mole) 2372
Li Be B C N O F Ne 520 900 801 1087 1402 1314 1681 2081
Na Mg Al Si P S Cl Ar 496 738 578 787 1012 1000 1256 1521
K Ca Ga Ge As Se Br Kr 419 590 579 761 947 941 1140 1351
Rb Sr In Sn Sb Te I Xe 403 550 558 708 834 869 1008 1170
Cs Ba Tl Pb Bi Po At Rn 376 503 589 716 703 813 916 1037 Fr Ra 393 509