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9.04 Periodic Table and Periodic Trends 9.04 Periodic Table and Periodic Trends Dr. Fred O Garces Chemistry 152 Miramar College 1 9.04 Periodic Table and Periodic Trend 05.2015 The Periodic Table and the Elements What is the periodic table ? What information is obtained from the table ? How can elemental properties be predicted base on the PT ? 2 9.04 Periodic Table and Periodic Trend 05.2015 The Periodic Table A map of the building block of matter. I like to refer to the periodic table as a map of the building block of matter. Consider the value of a map. A map of California for example shows you the terrain and geological information of California. According to the map, the east is the Sierra Nevada, the west is the Pacific Ocean, the north is Portland and south is Baja California. Like wise the periodic table provides valuable information. The PT shows family and periods. The southwest (lower-left) portion of the Periodic table are the most metallic while the northeast (upper-right) is the most nonmetallic. Other information about the periodic table will be describe in this chapter. 1 18 IA VIIIA 1 2 13 14 15 16 17 2 1 H IIA Periodic Table IIIA IVA VA VIA VIIA He 1.00797 4.0026 3 4 5 6 7 8 9 10 2 Li Be B C N O F Ne 6.939 9.0122 10.811 12.0112 14.0067 15.9994 18.9984 20.179 11 12 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 3 Na Mg IIIB IVB VB VIB VIIB VIIIB IB IIB Al Si P S Cl Ar 22.9898 24.305 26.9815 28.086 30.9738 32.064 35.453 39.948 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 39.102 40.08 44.956 47.90 50.942 51.996 54.9380 55.847 58.9332 58.71 63.54 65.37 65.37 72.59 74.9216 78.96 79.909 83.80 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 5 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe 85.47 87.62 88.905 91.22 92.906 95.94 [99] 101.07 102.905 106.4 107.870 112.40 114.82 118.69 121.75 127.60 126.904 131.30 55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 6 Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn 132.905 137.34 138.91 178.49 180.948 183.85 186.2 190.2 192.2 195.09 196.967 200.59 204.37 207.19 208.980 [210] [210] [222] 87 88 89 104 105 106 107 108 109 7 Fr Ra Ac Ku [223] [226] [227] [260] http://www.chemsoc.org/viselements/pages/periodic_table.html 3 9.04 Periodic Table and Periodic Trend 05.2015 Periodic Table - e configuration from the periodic periodic table Electron configuration of an element is simply a listing of how many electrons are in each energy level of the atom for a particular element. The best way to determine of an element is to use the periodic table. In 1 18 IA VIIIA lecture notes 3.5, this was discussed. 2 13 14 15 16 17 1 H IIA IIIA IVA VA VIA VIIA He 1s1 1s2 2 Li Be B BC N O F Ne 2s1 2s2 2p1 2p2p12 2p3 2p4 2p5 2p6 Na Mg 3 4 5 6 7 8 9 10 11 12 Cl 3 IIIB IVB VB VIB VIIB VIIIB IB IIB Al Si P S Ar 3s1 3s2 3p1 3p2 3p3 3p4 3p5 3p6 4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Be Kr 4s1 4s2 3d1 3d2 3d3 4s13d5 3d5 3d6 3d7 3d8 4s13d10 3d10 4p1 4p2 4p3 4p4 4p5 4p6 5 Rb Sr Y Zr Nb Mo Tc Ru Rh Ni Ag Cd In Sn Sb Te I Xe 2 5s1 5s 4d1 4d2 4d3 5s14d5 4d5 4d6 4d7 4d8 5s14d10 4d10 5p1 5p2 5p3 5p4 5p5 5p6 6 Cs Ba La Hf Ta W Re Os Ir Ni Au Hg Tl Pb Bi Po At Rn 1 2 3 1 5 5 6 7 6s 6s2 5d1 5d 5d 6s 5d 5d 5d 5d 5d8 6s15d10 5d10 6p1 6p2 6p3 6p4 6p5 6p6 7 Fr Ra Ac Rf Db Sg Bh Hs Mt 7 7s1 7s2 6d1 6d2 6d3 7s16d5 6d5 6d6 6d 4 9.04 Periodic Table and Periodic Trend 05.2015 Periodic Table: electron behavior The periodic table can be classified by the behavior of their electrons It is important to note that when writing out the electron configuration for the elements, metals tend to have fewer electrons in their valence orbitals than nonmetals. When atoms try to attain the noble gas electron configuration, they tend to take the path of least resistance. Metals can attain a noble gas electron configuration more easily by losing electrons (therefore becoming cations) while nonmetals will attain a noble gas electron configuration by gaining electrons (therefore becoming anions). 1 18 IA VIIIA 2 13 14 15 16 17 1 IIA IIIA IVA VA VIA VIIA 2 3 4 5 6 7 8 9 10 11 12 3 IIIB IVB VB VIB VIIB VIIIB IB IIB 4 West (South) Mid-plains East (North) METALS METALLOID NON-METALS Alkali Noble gas 5 Alkaline Halogens Transition Calcogens 6 These elements These elements These elements tend to give up will give up e- or tend to accept 7 e- and form accept e- e- and form CATIONS ANIONS 5 9.04 Periodic Table and Periodic Trend 05.2015 2. Trend in Atomic Radius Atomic Radius: The size of at atomic specie is determine by the boundaries of the valence e-. Largest atomic species are those found in the southwest (SW) or bottom-left corner of the periodic table since these atoms have their valence electron found in a higher shell than the proceeding element above it in the periodic table. For example, elements with trends of increasing size goes, Li < Na , K < Rb for the Alkali family. For the chalcogen, the trend is O < S < Se < Te. Te has its valence electrons in the 5th shell and Se has its valence electrons in the 4th shell. Therefore, Te is bigger than O. Across the periodic table, the atomic radius decreases. The smallest atoms are found in the northeast (NW) or top-right corner of the periodic table. This trend follows Z(effective), which means that for elements in the same period, the valence electrons are all found in the same shell. For a given period, elements to the right (east) of the periodic table have more protons than those to the left (west) of the periodic table. This effectively causes the electron cloud in the valence shell to contract towards the nucleus where they are attracted to the proton. Therefore, the atomic radius decreases across the periodic table. For the third period, the atomic radius essentially goes Al > Si > P > S > Cl > Ar. In this example, Chlorine is smaller than S because although Cl has 7 valence electrons found in the 3rd shell, these electrons are attracted by 17 protons. Sulfur on the other hand has six valence electrons attracted by only 16 protons. Seventeen protons attracting the valence electrons in chlorine is more effective in decreasing the atomic radius than sixteen protons of sulfur. 6 9.04 Periodic Table and Periodic Trend 05.2015 2. Trend in Atomic Radius 7 9.04 Periodic Table and Periodic Trend 05.2015 3. Trend in Ionization Potential Ionization potential: Ionization energy or potential energy is defined as the energy required to remove the valence electron from an atomic specie. Ionization energy increases moving towards the NE corner or top- right corner of periodic table. The lowest ionization energy is towards the SW or bottom-left corner of the periodic table. The ionization energy is opposite the trend of atomic radii. This can be rationalize by thinking about the attraction of the valence electrons to the nucleus where the protons are located. For very small atoms, the valence electrons are closer to the protons and therefore the energy required to remove these valence electrons will be high. For larger atoms, the valence electrons are further away from the nucleus and therefore are not held as tightly. Larger atoms will have smaller ionization energy. There are some anomallies in this general trend that can be explained by how the electrons are arranged in the orbitals. Exercise - In general the ionization energy increase when moving towards the non mental (right-top) portion of the periodic table. Why is it therefore that the ionization energy for oxygen (1314 kJ/ mol is lower in energy than nitrogen 1402 kJ/mol, see table below 8 9.04 Periodic Table and Periodic Trend 05.2015 3. Trend in Ionization Potential 9 9.04 Periodic Table and Periodic Trend 05.2015 4. Trend in Electron Affinity Electron Affinity: Electron affinity is defined as the energy released (therefore the negative sign, see table) when an electron is added to the valence shell of an atom.
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