The Periodic The Periodic Table and Table and

Periodic LawPeriodic LawChapter 6Chapter 6

Section 6.1: Development of Section 6.1: Development of the Modern Periodic Tablethe Modern Periodic Table

Late 1790’s- Lavoisier compiled a list Late 1790’s- Lavoisier compiled a list of 23 elements known at the time of 23 elements known at the time

By 1870- 70 known elementsBy 1870- 70 known elements John NewlandsJohn Newlands

Arranged elements by increasing atomic Arranged elements by increasing atomic massmass

Noticed properties repeated every Noticed properties repeated every eighth element (periodic) eighth element (periodic)

Law of OctavesLaw of Octaves

Dmitri MendeleevDmitri Mendeleev

RussianRussian 11stst periodic table periodic table Organized elements by Organized elements by propertiesproperties

Arranged elements by Arranged elements by atomic massatomic mass

Predicted existence of Predicted existence of several unknown elementsseveral unknown elements

Element 101 Element 101 Mendeleevium (Md)Mendeleevium (Md)

Henry Moseley

1913-performs 1913-performs experiments to determine experiments to determine the atomic number of the the atomic number of the known elementsknown elements

Afterwards arranges the Afterwards arranges the elements in the periodic elements in the periodic table table listing them by listing them by increasing atomic number increasing atomic number instead of by massinstead of by mass

Periodic LawPeriodic Law

When the elements are arranged When the elements are arranged in order of increasing atomic in order of increasing atomic number, there is a periodic number, there is a periodic repetition of their repetition of their physical and physical and chemical propertieschemical properties

The Modern Periodic TableThe Modern Periodic Table Groups- aka Groups- aka familiesfamilies (vertical (vertical

columns)columns) Each group is numbered 1-8 followed by Each group is numbered 1-8 followed by

the letter A or Bthe letter A or B Representative Elements-Representative Elements- designated designated

with an A (1A-8A)with an A (1A-8A) Transition Elements-Transition Elements- designated with designated with

a B (3B-12B)a B (3B-12B) 18 total groups18 total groups elements of any one group have similar elements of any one group have similar

physical and chemical propertiesphysical and chemical properties

Periods- horizontal rowsPeriods- horizontal rows 7 total periods7 total periods element properties change as you go element properties change as you go

across each rowacross each row the pattern of properties repeats from the pattern of properties repeats from

one period to the next one period to the next

Classifying the ElementsClassifying the Elements Three main classifications for the Three main classifications for the

elementselements MetalsMetals NonmetalsNonmetals MetalloidsMetalloids

MetalsMetals Physical PropertiesPhysical Properties

Luster (shininess)Luster (shininess) Good conductors of heat and electricityGood conductors of heat and electricity High density (heavy for their size)High density (heavy for their size) High melting pointHigh melting point Ductile (most metals can be drawn out into thin wires)Ductile (most metals can be drawn out into thin wires) Malleable (most metals can be hammered into thin Malleable (most metals can be hammered into thin

sheets)sheets) Chemical PropertiesChemical Properties

Easily lose valence electronsEasily lose valence electrons Corrode easilyCorrode easily

Alkali Metals-Alkali Metals- group 1A elements (except group 1A elements (except hydrogen)hydrogen)

Alkaline Earth Metals-Alkaline Earth Metals- group 2A elements group 2A elements

Metals Con’t.Metals Con’t.

Transition MetalsTransition Metals Group B elementsGroup B elements

Inner Transition MetalsInner Transition Metals Lanthanide- used as phosphors Lanthanide- used as phosphors

(substances that emit light when struck (substances that emit light when struck by electrons)by electrons)

ActinideActinide

NonmetalsNonmetals Physical PropertiesPhysical Properties

No luster (dull appearance)No luster (dull appearance) Poor conductor of heat and electricityPoor conductor of heat and electricity Brittle (breaks easily) or gaseousBrittle (breaks easily) or gaseous Not ductileNot ductile Not malleableNot malleable Low densityLow density Low melting pointLow melting point

Bromine is the only nonmetal liquid at room temperatureBromine is the only nonmetal liquid at room temperature Chemical PropertiesChemical Properties

  Tend to gain valence electronsTend to gain valence electrons

Nonmetals Con’tNonmetals Con’t

HalogensHalogens Group 7AGroup 7A Extremely ReactiveExtremely Reactive

Noble GasesNoble Gases Group 8AGroup 8A Extremely UnreactiveExtremely Unreactive

MetalloidsMetalloids

Bordering the stair-step line Bordering the stair-step line Physical Properties Physical Properties

SolidsSolids Can be shiny or dullCan be shiny or dull DuctileDuctile MalleableMalleable Conduct heat and electricity better than Conduct heat and electricity better than

nonmetals but not as well as metals nonmetals but not as well as metals

Elements in the same group on the Elements in the same group on the periodic table have similar chemical periodic table have similar chemical properties because they have the properties because they have the same same valence electron configurationvalence electron configuration

Section 6.3: Periodic TrendsSection 6.3: Periodic Trends

The electron cloud surrounding the The electron cloud surrounding the nucleus is based on the probability nucleus is based on the probability and does not have a clearly defined and does not have a clearly defined edgeedge

Atomic size is defined by how closely Atomic size is defined by how closely an atoms lies to a neighboring atoman atoms lies to a neighboring atom

Atomic Radii TrendAtomic Radii Trend Trends within Trends within

periodsperiods Generally Generally

decreases as you decreases as you move left-to-right move left-to-right across a period across a period (row)(row)

Trends within Trends within groupsgroups Generally Generally

increases as you increases as you move down a move down a groupgroup

Ionic RadiusIonic Radius

An An ionion is an atom or a bonded group is an atom or a bonded group of atoms that has a positive or of atoms that has a positive or negative chargenegative charge When atoms When atoms lose electronslose electrons and form and form

positivelypositively charged ions, they always charged ions, they always become become smallersmaller

When atoms When atoms gain electronsgain electrons and form and form negativelynegatively charged ions, they always charged ions, they always become become largerlarger

Lose Electrons Smaller ionic radii

Gain Electrons larger ionic radii

Ionization Energy (I.E.)Ionization Energy (I.E.)

Ionization Energy-Ionization Energy- the energy required the energy required to remove an electron from a gaseous to remove an electron from a gaseous atomatom

11stst Ionization Energy- removes the 1 Ionization Energy- removes the 1stst electronelectron

22ndnd Ionization Energy- removes the 2 Ionization Energy- removes the 2ndnd electron… and so forth electron… and so forth

I.E. is an indication on how strongly an I.E. is an indication on how strongly an atom’s nucleus holds onto its valence atom’s nucleus holds onto its valence electronselectrons

Octet Rule- atoms tend to gain, lose or share electrons in order to acquire a full set of eight valence electrons

Octet Rule- atoms tend to gain, lose or share electrons in order to acquire a full set of eight valence electrons Hydrogen and Helium are exceptions (they’ll

be happy with 2 V.E.) Determines the types of ions likely to form

Elements on the right side tend to gain electrons

Elements on the left side tend to lose electrons

ElectronegativityElectronegativity

Indicates the relative ability of its Indicates the relative ability of its atoms to attract electrons in a atoms to attract electrons in a chemical bondchemical bond Noble gases form very few compounds Noble gases form very few compounds

so they are left outso they are left out In a chemical bond, the atom with the In a chemical bond, the atom with the

greater electronegativity more strongly greater electronegativity more strongly attracts the bond’s electrons attracts the bond’s electrons

In SummaryIn Summary

Atomic radius decreasesIonization energy increasesElectronegativity increases

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Matching Words for TestMatching Words for Test

ElectronegativityElectronegativity Ionization energyIonization energy Atomic radiusAtomic radius MetalMetal Transition metalTransition metal AnionAnion

Periodic lawPeriodic law CationCation PeriodPeriod GroupGroup ElectronsElectrons NonmetalNonmetal

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