The Periodic Table- A Chemist’s Best Friend C-level Chapter 4 H-level Chapter 6 History Organizational Patterns Trends The Element Song

Part 1: Periodic Table History

Patterns in Element properties Groups of elements share certain properties –Li, Na, K, Rb, and Cs all combine with Cl in a 1:1 ration to form LiCl, NaCl, KCl, RbCl, and CsCl. All these compounds are white solids that dissolve in water to form solutions that conduct electricty

Dmitri Mendeleev By 1850, approximately 60 elements are known Dmitri Mendeleev in 1869 publishes the first periodic table 1.Arranged according to increasing atomic mass — noticed a trend in chemical and physical properties 2.Not all the elements had been discovered so he left blank spaces for undiscovered. 3.In these blank spaces the physical and chemical properties could be predicted. My friends call me “Father of the Periodic Table”

Mendeleev’s Periodic Table Published in 1871, St. Petersburg, Russia by Dmitrii I. Mendeleev

The Physical Basis of the Periodic Table Henry Moseley In 1913 arranged elements according to increasing atomic number. (Similar to Mendeleev because increasing atomic number is related to increased atomic mass.) This is the way they are still arranged today

The Periodic Law Periodic law: when the elements are arranged in order of increasing atomic number, elements with similar properties appear at regular intervals.

Our Modern PT H Li Na Cs Rb K LaBa Be Mg Sr Ca Y AcRa Sc Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es TlHgAuHfPtIrOsReWTa He RnAtPoBiPb CdAgZrPdRhRuTcMoNb ZnCuTiNiCoFeMnCrV InXeITeSbSn GaKrBrSeAsGe AlArClSPSi BNeFONC DbSgRfBhHsMt This arrangement takes too much space and is hard to read.

So we alter it a little H Li Na Cs Rb K LaBa Be Mg Sr Ca Y AcRa Sc Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es TlHgAuHfPtIrOsReWTa He RnAtPoBiPb CdAgZrPdRhRuTcMoNb ZnCuTiNiCoFeMnCrV InXeITeSbSn GaKrBrSeAsGe AlArClSPSi BNeFONC DbSgRfBhHsMt

Now it takes up less space H Li Na Cs Rb K LaBa Be Mg Sr Ca Y AcRa Sc Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es TlHgAuHfPtIrOsReWTa He RnAtPoBiPb CdAgZrPdRhRuTcMoNb ZnCuTiNiCoFeMnCrV InXeITeSbSn GaKrBrSeAsGe AlArClSPSi BNeFONC DbSgRfBhHsMt

Organization of the Periodic Table Electrons play the biggest role in determining periodic properties Each group (column) has similar properties Based on VALENCE electrons

Organization of the Periodic Table Valence electrons – e - s in the highest occupied energy level of an atom and determines the atom’s chemical properties Elements with same # valence e- tend to react in similar ways Electrons involved in bonding (F) 1s 2 2s 2 2p 5

Group Vertical column of elements in the periodic table; elements in a group share chemical properties. Groups named Groups go DOWN

Groups & Periods Transition Inner Transition 1A2A 3A 4A 5A 6A 7A 8A 3B 4B 5B 6B 7B ---8B---- 1B 2B s p d f Groups RepresentativeRep

He Rn XeI KrBrSe ArClS NeFO P NC H Li Na Cs Rb K TlHgAuHfLuBa Fr PtIrOsReWTaPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb LrRa ZnCuTiScNiCoFeMnCrV InSbSn GaGe Al Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No La Ac Er Fm Tm Md Dy Cf Ho Es At Te As Si B IA IIA IIIA IVA VA VIA VIIA VIII IIIB IVB VB VIB VIIB VIII IB IIB Groups can also be assigned Roman numerals & letters Groups can also be assigned Roman numerals & letters Topic 1.4 Groups / Families

Periods Horizontal rows Numbered one to seven Principal Quantum Number Atomic number increases by 1 with each jump to the right *No related properties along a period Periods go ACROSS

Part 2: Periodic Table Organization

Organization of the periodic table A. Periodic tables provide info for each element 1.atomic number -number of protons 2.Symbol 3.Name 4.Average atomic mass 5.Electron configurations 6.Physical state 7.Oxidation states

The Elements 115 elements are currently known 89 are metals 31 are radioactive 25 are synthetic (all radioactive) 11 occur as gases 2 occur as liquids –Let’s take a look at them on the table

Main Group elements Main group or Representative elements In the s or p blocks Number of valence electrons is the same for the whole group and corresponds to group number 4 groups have special names

Alkali Metals Group 1 Most reactive metals known - Cesium most reactive One valence e- that is given freely (s 1 ) Form Cations w/ +1 charge Not found free in nature because of high reactivity –Alkali metal salts are found throughout the world Named because the form alkaline solutions when they react with water Reactive with water & oxygen in air so must be stored under oil

Alkaline Earth Metals Group 2 Not as reactive as group 1, s orbital filled Have 2 valence electrons (s 2 ) Form Cations w/ +2 charge Some of the salts are found in the ocean Some of the salts are very insoluble in water Have higher melting points and are harder than alkali metals

Halogens Group 17 Non-metals Seven e - in valence shell, needs only 1 more e- for full valence Form Anions w/ -1 charge F most reactive and electronegative of all non-metals Reactivity decreases as you move down the group Do not exist naturally in the uncombined state Goes from gas (F, Cl) to liquid (Br) to solid (I, Ar)

Noble Gases Group 18 Also called Inert gases – do not usually react Outer s, p sublevels full except He (1s 2 ) They are happy with these electrons so they don’t need to gain or lose any – non-reactive

Hydrogen Hydrogen is in a class by itself with only 1 proton and 1 electron Unique not a metal, non-metal or metalloid Most abundant in the universe –~¾ of all atoms in the universe

Common family names H Li Na Cs Rb K TlHgAuHfLuBa Fr PtIrOsReWTa He RnAtPoBiPb Be Mg Sr Ca CdAgZrYPdRhRuTcMoNb LrRa ZnCuTiScNiCoFeMnCrV InXeITeSbSn GaKrBrSeAsGe AlArClSPSi BNeFONC GdTbSmEuNdPmCePrYbLaErTmDyHoCmBkPuAmUNpThPaNoAcFmMdCfEs Alkali metals Alkaline earth metals Halogens Noble gases Coinage Metals Chalcogens Lanthanides Actinides Topic 1.4

Most elements are metals Metals Left side of “staircase” Non-metals Right of staircase Metalloids Border staircase Properties of metals and nonmetals

Metals 1.Left side of staircase 2.Transition & Inner Transition 3.~ 2/3 of all elements Properties: Maleable hammered Ductile squeeze to a wire Lustrous Good Conductors Bonding: Lose e- when bonding CATIONS (+ charge)

Non-Metals 1.Right side of staircase Properties: Brittle Non-Conductors Bonding: Gain e- when bonding ANIONS (- charge)

Metalliods 1.Border staircase Properties: Both metal & non-metal properties Bonding: May gain or Lose e- when bonding Anions or Cations

Transition Metals Groups 3-12 d block – outer e-s in d- energy level Properties of metals Sum of s & d e-s = group number Often have more than one oxidation state (due to rules we don’t know yet) *Coinage metals (Ni, Cu, Ag, Au)

Lanthanides & Actinides f block - Filling f-sublevel 1. Lanthanides - atomic numbers follow the element lanthanum - shiny metals w/ reactivity similar to alkaline earth metals 2. Actinides -atomic numbers follow the element actinium - all are Radioactive U and Th – only two natural, rest are man made

Physical States An element’s physical state at room temp can be either solid, liquid, or gas. Only two are liquids: Hg and Br 11 are gases The remaining elements are solids.

Part 3: Periodic Trends Ionization Energy Atomic Radius Electronegativity Ionic Radius Periodic table has trends in the properties of the elements A predictable change in a particular direction Can be explained in terms of electron configuration

Group Trend Decrease down a group - more energy levels. - e - s further from the nucleus - e- not held as tightly Shielding – - Inner core e- between valence and nucleus. - shield the valence e-s from the full attractive force of the nucleus Larger atoms can’t hold outer e- well so lower IE than smaller atoms Period Trend Increase left to right - number of protons and e-s increases by 1. - p+ increases nuclear charge. - e- added to the same outer energy level, but shielding does not change Metals have less than ½ full valence, willing to give up electrons (IE low) Non-metals have more than ½ valence, not willing to give up electrons (IE high) Ionization Energy Energy required to remove one valence electron and create an ion.

First Ionization Energy –Increases UP and to the RIGHT Ionization Energy

Which atom has the higher 1st I.E.? –NorBi –BaorNe N Ne Examples

Removal of valence versus core electrons Na(g)Na + (g) + e - I 1 = 495 kJ/mol Na + (g)Na 2+ (g) + e - I 2 = 4560 kJ/mol [Ne]3s 1 [Ne] 1s 2 2s 2 2p 5 (removing “valence” electron) (removing “core” electron) Takes significantly more energy to remove a core electron Ionization Energy

Successive Ionization Energies –What group?1st I.E.736 kJ 2nd I.E.1,445 kJ 3rd I.E.7,730 kJ –Large jump in I.E. occurs when a CORE e - is removed. Ionization Energy

–What Group?1st I.E.577 kJ 2nd I.E.1,815 kJ 3rd I.E.2,740 kJ 4th I.E.11,600 kJ Successive Ionization Energies –Large jump in I.E. occurs when a CORE e - is removed. Ionization Energy

Atomic Radius Bond radius: half the distance between the nuclei of two like atoms r = bond radius

Group Trends Increases DOWN group –Higher energy levels have larger orbitals –Shielding – causes the effective nuclear charge action on the outer e-s to remain constant Period Trends Decreases left to right –Increased nuclear charge without additional shielding pulls e - in Atomic Radius

–Increases to the LEFT and DOWN Atomic Radius

Which atom has the larger radius? –BeorBa –CaorBr Ba Ca Examples

A measure of the ability of an atom in a chemical compound to attract electrons Cs least electronegative F is most electronegative Electronegativity

Periodic Trends –Left to right— increases –e- shielding remains constant, but more pull from nucleus Group Trends –Generally decreases as you move down –Outer e - s have more distance as you move down group

–Increases UP and to the RIGHT Electronegativity

–Cations (+) lose e - smaller © 2002 Prentice-Hall, Inc. –Anions (–) gain e - larger Periodic trends in ionic size

Ionic Radius Periodic Trends –From left to right decreases in size of positive ions –Starting with group 4 the anions (much larger) also decreases as you move right Group Trends Everything increases as you move down

Electron affinity The energy change that occurs when a neutral atom gains an e-s Group increases up Period increases to left

Melting/Boiling Point –Highest in the middle of a period. Melting/Boiling Point