Graphing Periodic Trends

Graphing Periodic Trends The Periodic Table is arranged according to Periodic Law. The Periodic Law states that when elements are arranged in order of increasing atomic number, their physical and chemical properties show a periodic pattern. These patterns can be discovered by examining the changes in properties of elements on the Periodic Table. The properties that will be examined in this lesson are: atomic size, electronegativity, and ionization energy. Procedure 1. Use excel (office 365) or a similar program to create 3 graphs (scatterplot – straight link connections between data points). Give the graph an appropriate title and label the axes (the x-axis is ‘atomic number’ for all graphs). 2. Cut and paste the graphs onto a word document so that their x-axes are in line. 3. Label/high-light the data points with the symbol of each alkali metal, halogen and noble gas. 4. Use your graphs to complete the analysis questions (type your response in a different colour!). below. Post your completed assignment to your edublog (2 students may post identical assignments) using the tag: mstilsnerchem11coop 1. Data Table X Y1 Y2 Y3 Element Symbol Atomic # Atomic Radius (pm) 1st Ionization Energy (kJ/mol) Electronegativity *(Pauling Scale) H 1 53 1311 2.20 He 2 31 2371 0 Li 3 167 520 0.98 Be 4 112 899 1.57 B 5 87 800 2.04 C 6 67 1086 2.55 N 7 56 1402 3.04 O 8 48 1313 3.44 F 9 42 1680 3.98 Ne 10 36 2080 0 Na 11 190 496 0.93 Mg 12 145 737 1.31 Al 13 118 577 1.61 Si 14 111 786 1.90 P 15 98 1011 2.19 S 16 88 999 2.58 Cl 17 79 1251 3.16 Ar 18 71 1520 0 K 19 243 419 0.82 Ca 20 194 590 1.00 Sc 21 184 633 1.36 Ti 22 176 659 1.54 V 23 171 651 1.63 Cr 24 166 653 1.66 Mn 25 161 717 1.55 Fe 26 156 762 1.83 Co 27 152 760 1.88 Ni 28 149 737 1.91 Cu 29 145 745 1.90 Zn 30 142 906 1.65 Ga 31 136 579 1.81 Ge 32 125 762 2.01 As 33 114 944 2.18 Se 34 103 941 2.55 Br 35 94 1139 2.96 Kr 36 88 1350 0 Atomic Number vs. Atomic Radius Atomic radius (Pm) 12 10 8 6 4 2 0 0 2 4 6 8 10 12 10 12 10 12 Electronegativity (Pauling Scale) 1st Ionization Energy (KJ/mol) Atomic number Atomic Number vs. 1st Ionization Energy 12 10 8 6 4 2 0 0 2 4 6 8 Atomic Number Atomic Number vs. electronegativity 12 10 8 6 4 2 0 0 2 4 6 8 Atomic Number ANALYSIS QUESTIONS: use the periodic table below to summarize the following trends. 1. Based on your graphs, what is the trend in atomic radius across a period? Down a family? The trend is to spike up in the alkali metals and shrink across the period. They tend to get bigger down a family. 2. Based on your graphs, what is the trend in ionization energy across a period? Down a family? The trend is to be low at the alkali metals and rise toward the noble gases. They tend to get lower down a family. 3. Based on your graphs, what is the trend in electronegativity across a period? Down a family? The trend is to be low at the noble gases then rise to the halogens. They tend to get lower down a family but they are pretty close together. 4a) What is happening to the number of protons and the number of energy levels as you move across the periodic table from left to right? How and why does this affect atomic radius. The number of protons rises and the number of energy levels rises. This affects the atomic radius by making them smaller across the period, because opposites attract so the electrons are pulled into the nucleus. b) What happens to the number of energy levels as you move down a column on the periodic table. How and why does this effect ionization energy? The energy level gets lower because the atomic radius gets bigger and the outer electrons are more loosely held therefore making the ionization energy lower down the family. c) What happens to the effective nuclear charge as you move across a period on the periodic table? How does this effect ionization energy and electronegativity? The effective nuclear charge increases across a period, therefore increasing ionization energy and electronegativity also increases. 5a) Which group contains elements which are easiest to ionize? Explain why this is the case. The alkali metals are the easiest because the atomic radius is large and they have 1 valence electron b) Explain why the third ionization energy of Ca would be much higher than the 1st and 2nd ionization energy Ca The third ionization energy of Ca would be higher because it has more protons. 6. Which element would have the highest electronegativity in each set below? Explain why this is. a) Ca, Be or Mg b) B, Li, or F a) Be, because it is at the top of a family and the electronegativity gets lower going down the family. b) F, because the electronegativity gets higher across the period and F is at a halogen at the end. 7. Write (or type) the electron configuration of each atom (high-light the valence electrons) and it’s corresponding ion below each sketch (atomic radii are given in angstroms (1 x 10-10 M). N = 1s2 2s2 2p3 N3- = 1s2 2s2 3p6 O = 1s2 2s2 2p4 O2- = 1s2 2s2 2p6 F = 1s2 2s2 2p5 F- = 1s2 2s2 2p6 Na = 1s2 2s2 2p6 Na+ = 1s2 2s2 2p5 Mg = 1s2 2s2 2p6 3s2 Mg2+ = 1s2 2s2 2p6 Al = 1s2 2s2 2p6 3s2 3p1 Al3+ = 1s2 2s2 2p6 9. Over the blank periodic table provided, write or type the number of valence electrons and the expected ion charge for the transition metal block and for the families to the left and right of the transitions metals (the alkali metals have been done as an example). Note: Carbon and boron do not normally form ions and are thus blanked-out # valence e: 1 2 | Ion charge: +1 +2 | 3-12 | 3 +1 +2 | +3 4 5 6 7 8 -3 -2 -1 0