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 arrange-ment 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 QuantizedThey 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 # of orbitals # of electrons

s 1 2

p 3 6

d 5 10

f 7 14

Shapes of OrbitalsAn 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 Fillingfor 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.

PERIO DIC TABLE OF THE ELEM ENTS1 17 18

1A 7A 8A

1 1 2

H H HeHydrogen 2 13 14 15 16 Hydrogen Helium

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 NeLithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon

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 M g Al Si P S Cl ArSodium Magnesium 3 4 5 6 7 8 9 10 11 12 Alum inum Silicon Phosphorus Sulfur Chlorine Argon

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

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

K Ca Sc Ti V Cr M n Fe Co Ni Cu Zn Ga Ge As Se Br KrPotassium Calcium Scandium Titanium Vanadium Chrom ium Manganese Iron Cobalt N ickel Copper Zinc Gallium Germ anium Arsenic Selenium Brom ine Krypton

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 M o Tc Ru Rh Pd Ag Cd In Sn Sb Te I XeRubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadm ium Indium Tin Antim ony Tellurium 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 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86

Cs Ba *La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At RnCesium Barium Lanthanum Hafnium Tantalum Tungsten Rhenium Osm ium Iridium Platinum Gold Mercury Thallium Lead Bism uth Polonium Astatine Radon

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 M tFrancium Radium Actinium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium

(223) 226.0254 227.0278 (261) (262) (266) (264) (269) (268) (271) (272) (277) (289) (289) (293)

58 59 60 61 62 63 64 65 66 67 68 69 70 71

*Lanthanide Series Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb LuCerium Praesodym ium Neodym ium Prom ethium Sam arium Europium Gadolinium Terbium Dysprosium Holm ium Erbium Thulium Ytterbium 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 91 92 93 94 95 96 97 98 99 100 101 102 103

**Actinide Series Th Pa U Np Pu Am Cm Bk Cf Es Fm M d No LrThorium Protactinium Uranium Neptunium Plutonium Am ericium Curium Berkelium Californium Einsteinium Ferm ium Mendelevium Nobelium Lawrencium

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: Representative MetalsOrange: Transition MetalsYellow: Inner Transition MetalsPurple: Post-Transition Metals Aqua: Metalloids, a.k.a SemimetalsGreen: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 at-traction 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.