History of the Periodic Table Each group will be given some cards. Can your group figure out what card is missing? What is it (number and suit)?

Antoine Lavoisier In the late 1790s, he compiled a list of the known elements at the time. In the late 1790s, he compiled a list of the known elements at the time. This list contained 23 elements. This list contained 23 elements

But times were about to change… In the 1800’s, there were many changes in the world In the 1800’s, there were many changes in the world ElectricityElectricity SpectrometerSpectrometer Industrial RevolutionIndustrial Revolution As a result, there was an increase in the number of known elements As a result, there was an increase in the number of known elements By the 1870, there were 70 known elementsBy the 1870, there were 70 known elements

An agreement is reached… Then in the 1860’s, chemist agreed upon a method for accurately determining the atomic mass of elements. Then in the 1860’s, chemist agreed upon a method for accurately determining the atomic mass of elements.

John Newlands Noticed when elements were arranged by atomic mass, they repeated properties every 8 th element. Noticed when elements were arranged by atomic mass, they repeated properties every 8 th element. He used the word periodic to describe this pattern He used the word periodic to describe this pattern He gave it the name the Law of Octaves He gave it the name the Law of Octaves

Unfortunately… Did not work for all the elements Did not work for all the elements Criticized because of its association with music Criticized because of its association with music Did give others the idea of repeating properties - periodic Did give others the idea of repeating properties - periodic We Hate It

Lothar Meyer and Dmitri Mendeleev Each made a connection between atomic mass and properties of elements Each made a connection between atomic mass and properties of elements

The winner is… Mendeleev is given credit because his was published first Mendeleev is given credit because his was published first In addition, Mendeleev predicted unknown elements In addition, Mendeleev predicted unknown elements However, not completely correct – new elements weren’t in correct order However, not completely correct – new elements weren’t in correct order What do you notice about elements 27 & 28 and 52 & 53? What do you notice about elements 27 & 28 and 52 & 53? Mendeleev

Henry Moseley Solved this problem by arranging the elements by increasing atomic number. Solved this problem by arranging the elements by increasing atomic number. The periodic repetition of chemical and physical properties of elements when arranged by atomic number is now known as Periodic Law The periodic repetition of chemical and physical properties of elements when arranged by atomic number is now known as Periodic Law

Which leads to the Modern Periodic Table Boxes each with: Boxes each with: H 1 Hydrogen Element Name Atomic Number Atomic Symbol Atomic Mass That are arranged by increasing atomic numbers

Remember Atomic number = the number of protons = the number of electrons (if neutral) Atomic number = the number of protons = the number of electrons (if neutral) Atomic Mass on the Periodic table is the average mass of the isotopes Atomic Mass on the Periodic table is the average mass of the isotopes But the mass number of each isotope is the protons plus the neutronsBut the mass number of each isotope is the protons plus the neutrons

Chemical Symbol The symbol that refers to the element The symbol that refers to the element First letter is capitalized, second letter (if applicable) is lower case First letter is capitalized, second letter (if applicable) is lower case Not all symbols are based on English names for the elements, some come from their Latin names or even other languages Not all symbols are based on English names for the elements, some come from their 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 Rows The columns are called Families or Groups The columns are called Families or Groups Earlier Version had 1-8 followed by A or BEarlier Version had 1-8 followed by A or B Group A elements are called Representative Elements Group A elements are called Representative Elements Group B elements are called Transition Elements Group B elements are called Transition Elements Modern Version labels the columns with 1-18Modern Version labels the columns with 1-18 Rows are called Periods Rows are called Periods Seven periods for the seven energy levels (rings)Seven periods for the seven energy levels (rings)

Classifying Elements Three Types of Elements Three Types of Elements MetalsMetals NonmetalsNonmetals MetalloidsMetalloids

Metals Shiny when smooth and clean Shiny when smooth and clean Solid at room temperature Solid at room temperature Only exception - MercuryOnly exception - Mercury Good conductors of heat and electricity Good conductors of heat and electricity Most are ductile and malleable Most are ductile and malleable

Most of the elements on the table are metals, which are in blue

Nonmetals Upper Right side of the Periodic Table Upper Right side of the Periodic Table Generally brittle solids or gases Generally brittle solids or gases Poor conductors of heat and electricity Poor conductors of heat and electricity Bromine is the only liquid at room temperature Bromine is the only liquid at room temperature

“The Yellow Elements”

Metalloids A.k.a – the semi-metals A.k.a – the semi-metals Boxes bordering the stair-step Boxes bordering the stair-step Physical and chemical characteristics of both metals and nonmetals Physical and chemical characteristics of both metals and nonmetals

“The Green Stair-stepping Elements”