Chapter 6. Electronic Structure and Chemical Periodicity The Periodic Law states that when elements are arranged in order of increasing atomic number, elements with similar chemical properties occur at periodic (regularly spaced) intervals. Tom Lehrer's Elements in Song The Periodic Table A Periodic Table is a tabular arrangement of the elements, in order of atomic number, in which elements with similar chemical properties are grouped in columns. Several attempts were made to group elements in the mid-1800's. The one that worked was developed in Russia, by Dmitri Mendeleev, in 1869. Dmitri Mendeleev Mendeleev's Periodic Table Mendeleev's Predictions for Undiscovered Elements Periodic Table of the Elements The Periodic Table and Electronic Structure of Atoms The Periodic Law follows from the electronic structures of atoms. The outermost electrons in the atoms of an element are responsible its properties. Valence electrons, or distinguishing electrons, are the outermost electrons in an atom. Electron Energies are Quantized They Occur in steps Atomic Spectra of Elements Steps Within the Steps An Electron Shell is a region of space around a nucleus that contains electrons that have similar energies, and similar distances from the nucleus. An Electron Subshell is a subdivision of a shell, in which all the electrons have exactly the same energy and distance from the nucleus. An Electron Orbital is a region of space in a subshell where one or two electrons with a specific energy are likely to be found. Electron Shells and Subshells Electron Shells and Subshells Steps Within the Steps An Electron shell contains 2(n2) electrons Electron subshells have characteristic numbers of orbitals and electrons. Subshell s p d f # of orbitals 1 3 5 7 # of electrons 2 6 10 14 Shapes of Orbitals An Electron Orbital is a region of space in a subshell where one or two electrons with a specific energy are likely to be found. How Three p Orbitals Make up a p Subshell Energy Levels of Subshells Get a Bit Shuffled Aufbau Diagram: Order of Filling for Subshells Periodic Table, Showing Subshells That Contains Valence Electrons for Various Elements Periodic Table, Showing Shell Number for Valence Electrons Periodic Table Showing How Inner Transition Elements Fit into the Main Table The modern Periodic Table. Elements with similar chemical properties fall in the same vertical column. P E R IO D IC T A B L E O F T H E E L E M E N T S 1 17 18 1A 7A 8A 1 1 2 H H He H ydrogen 2 13 14 15 16 H ydrogen H elium 1.00794 2A 3A 4A 5A 6A 1.00794 4.00260 3 4 5 6 7 8 9 10 Li Be B C N O F Ne Lithium B eryllium B oron C arbon N itrogen O xygen F luorine N eon 6.941 9.01218 10.81 12.011 14.0067 15.9994 18.998403 20.1797 11 12 13 14 15 16 17 18 Na Mg Al Si P S Cl Ar S odium M agnesium 3 4 5 6 7 8 9 10 11 12 A lum inum S ilicon P hosphorus S ulfur C hlorine A rgon 22.98977 24.305 3B 4B 5B 6B 7B 8B 8B 8B 1B 2B 26.98154 28.0855 30.97376 32.066 35.453 39.948 25 26 29 30 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr P otassium 19 C alcium S candium T itanium V anadium C hrom ium M anganese Iron C obalt N ick el C opper Z inc G allium G erm anium A rsenic S elenium B rom ine K rypton 39.0983 40.078 44.9559 47.88 50.9415 51.996 54.9380 55.847 58.9332 58.69 63.546 65.39 69.72 72.61 74.9216 78.96 79.904 83.80 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe R ubidium S trontium Y ttrium Z irconium N iobium M olybdenum T echnetium R uthenium R hodium P alladium S ilver C adm ium Indium T in A ntim ony T ellurium Iodine Xenon 85.4678 87.62 88.9059 91.224 92.9064 95.94 (98) 101.07 102.9055 106.42 107.8682 112.41 114.82 118.710 121.757 127.60 126.9045 131.29 55 20 56 21 22 57 72 23 73 24 74 75 76 27 77 28 32 33 78 79 81 82 Ba *L a Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Lanthanum H afnium T antalum T ungsten R henium O sm ium Iridium P latinum G old M ercury T hallium Lead B ism uth P olonium A statine R adon 132.9054 137.33 138.9055 178.49 180.9479 183.85 186.207 190.2 192.22 195.08 196.9665 200.59 204.383 207.2 208.9804 (209) (210) (222) 87 88 89 104 105 106 107 108 109 110 111 112 114 116 118 Fr Ra **Ac Rf Db Sg Bh Hs Mt (271) (272) (277) (289) (289) (293) R adium A ctinium R utherfordium D ubnium S eaborgium B ohrium H assium M eitnerium 227.0278 (261) (262) (266) (264) (269) (268) *L a n th a n id e S e rie s 86 58 59 60 61 62 63 64 65 66 67 68 69 70 71 Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu C erium P raesodym ium N eodym ium P rom ethium S am arium E uropium G adolinium T erbium D ysprosium H olm ium E rbium T hulium Y tterbium Lutetium 140.12 140.9077 144.24 (145) 150.36 151.96 157.25 158.9254 162.50 164.9304 167.26 168.9342 173.04 174.967 90 **Ac tin id e S e rie s 85 36 B arium 226.0254 84 35 Cs (223) 83 34 C esium F rancium 80 31 91 92 93 94 95 96 97 98 99 100 101 102 103 Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr T horium P rotactinium U ranium N eptunium P lutonium A m ericium C urium B erk elium C alifornium E insteinium F erm ium M endelevium N obelium Law rencium 232.0381 231.0359 238.0289 237.048 (244) (243) (247) (247) (251) (252) (257) (258) (259) (262) Vocabulary of Periodic Table Group (family) of elements--vertical column Period (row) of elements--horizontal row Group 1A: Alkali Metals Group 2A: Alkaline Earth Metals Group 7A: Halogens Group 8A: Noble Gases Groups 1A – 8A: Representative Elements Groups 1B – 8B: Transition Metals Vocabulary of Periodic Table Pink: Orange: Yellow: Purple: Aqua: Green: Representative Metals Transition Metals Inner Transition Metals Post-Transition Metals Metalloids, a.k.a Semimetals Nonmetals Properties of Metals, Metalloids, and Nonmetals. Metals Metalloids (Semimetals) Nonmetals Conductors of Electricity Semiconductors of Electricity Insulators of Electricity Conduct Heat Well Conduct Heat Poorly Metallic Luster Metallic Luster No Metallic Luster Solid at Room Temp Solid at Room Temp State Varies with Molar Mass Malleable and Ductile Brittle Brittle Effective Nuclear Charge (Zeff) Zeff is the charge actually felt by an electron Outer electrons are shielded by inner electrons. Relative Sizes of Main Group Atoms Ionization Energy is the energy required to pull an electron off an atom. Electron Affinity is the energy released when a neutral atom gains an electron. Electronegativity is a measure of the attraction an atom has for electrons it is sharing in a chemical bond. Cations are positively charged atoms that have lost electrons. They are always smaller than the parent atom. Anions are negatively charged atoms that have gained electrons. They are always larger than the parent atom.