History of the Periodic History of the Periodic TableTable
Each group will be given some cards. Can your group figure out what card is missing? What is it (number
and suit)?
Antoine LavoisierAntoine Lavoisier In the late 1790s, In the late 1790s,
he compiled a list he compiled a list of the known of the known elements at the elements at the time.time.
This list contained This list contained 2323 elements. elements.
1743 - 1794
But times were about to change…But times were about to change…
In the 1800’s, there were many In the 1800’s, there were many changes in the worldchanges in the world• ElectricityElectricity• SpectrometerSpectrometer• Industrial RevolutionIndustrial Revolution
As a result, there was an increase in As a result, there was an increase in the number of known elementsthe number of known elements• By the 1870, there were By the 1870, there were 7070 known known
elementselements
An agreement is reached…An agreement is reached… Then in the 1860’s, chemist agreed Then in the 1860’s, chemist agreed
upon a method for accurately upon a method for accurately determining the determining the atomic massatomic mass of of elements.elements.
John NewlandsJohn Newlands Noticed when elements Noticed when elements
were arranged by were arranged by atomic atomic massmass, they repeated , they repeated properties every properties every 88thth element.element.
He used the word He used the word periodicperiodic to describe this to describe this patternpattern
He gave it the name the He gave it the name the LawLaw of of OctavesOctaves
1838-1898
Unfortunately…Unfortunately… Did notDid not work for all the elements work for all the elements Criticized because of its association with Criticized because of its association with
musicmusic Did give others the idea of repeating Did give others the idea of repeating
properties - properties - periodicperiodicWe Hate It
Lothar Lothar MeyerMeyer and Dmitri and Dmitri MendeleevMendeleev
Each made a connection between Each made a connection between atomic massatomic mass and and propertiesproperties of of elementselements
1830-1895 1834 - 1907
The winner is…The winner is…
Mendeleev is given credit because Mendeleev is given credit because his was his was publishedpublished first first
In addition, Mendeleev predicted In addition, Mendeleev predicted unknownunknown elements elements
However, not completely correct – However, not completely correct – newnew elements weren’t in elements weren’t in correctcorrect orderorder
What do you notice about elements What do you notice about elements 27 & 28 and 52 & 53?27 & 28 and 52 & 53?
MendeleevMendeleev
Henry MoseleyHenry Moseley Solved this problem by Solved this problem by
arranging the elements arranging the elements by increasing by increasing atomic atomic number.number.
The The periodicperiodic repetition repetition of chemical and of chemical and physical properties of physical properties of elements when elements when arranged by atomic arranged by atomic numbernumber is now known is now known as as PeriodicPeriodic Law Law
1887-1915
Which leads to the Modern Periodic Which leads to the Modern Periodic TableTable
Boxes each with:Boxes each with:
H1
Hydrogen
1.00794
Element Name
Atomic Number
Atomic Symbol
Atomic Mass
That are arranged by increasing atomic numbers
RememberRemember Atomic number = the number of Atomic number = the number of
protonsprotons = the number of = the number of electronselectrons (if (if neutral) neutral)
Atomic Mass on the Periodic table is Atomic Mass on the Periodic table is the average mass of the the average mass of the isotopesisotopes• But the mass number of each isotope is But the mass number of each isotope is
the the protonsprotons plus the plus the neutronsneutrons
Chemical SymbolChemical Symbol The symbol that refers to the The symbol that refers to the elementelement First letter is First letter is capitalizedcapitalized, second letter (if , second letter (if
applicable) is applicable) is lowerlower case case Not all symbols are based on English Not all symbols are based on English
names for the elements, some come from names for the elements, some come from their Latin names or even other languagestheir Latin names or even other languages
– Silver – Ag – argentum– Antimony – Sb -stibium – Lead – Pb – plumbum – Copper – Cu – cyprium
– Tin – Sn – stannum– Iron – Fe - ferrum– Mercury – Hg - hydrargyrum– Gold – Au - aurum
Columns and RowsColumns and Rows The columns are called The columns are called FamiliesFamilies or or
GroupsGroups• Earlier Version had 1-8 followed by A or BEarlier Version had 1-8 followed by A or B
Group A elements are called Group A elements are called RepresentativeRepresentative Elements Elements Group B elements are called Group B elements are called TransitionTransition Elements Elements
• Modern Version labels the columns with 1-18Modern Version labels the columns with 1-18
Rows are called Rows are called PeriodsPeriods• Seven Seven periodsperiods for the seven for the seven energy levelsenergy levels (rings) (rings)
Classifying ElementsClassifying Elements Three Types of ElementsThree Types of Elements
• MetalsMetals• NonmetalsNonmetals• MetalloidsMetalloids
MetalsMetals ShinyShiny when smooth and clean when smooth and clean SolidSolid at room temperature at room temperature
• Only exception - Only exception - MercuryMercury GoodGood conductors of heat and conductors of heat and
electricityelectricity Most are Most are ductileductile and and malleablemalleable
NonmetalsNonmetals Upper RightUpper Right side of the Periodic side of the Periodic
TableTable Generally Generally brittlebrittle solids or solids or gasesgases PoorPoor conductors of heat and conductors of heat and
electricityelectricity BromineBromine is the only liquid at room is the only liquid at room
temperaturetemperature
MetalloidsMetalloids A.k.a – the A.k.a – the semi-metalssemi-metals Boxes bordering the Boxes bordering the stair-stepstair-step Physical and chemical characteristics Physical and chemical characteristics
of of bothboth metals and nonmetals metals and nonmetals
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