Periodic Table HistoryPeriodic Table History• Dmitri Mendeleev

(1869)• Creates periodic

table with elements listed in increasing mass.

• Finds that properties repeat in the table.

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[http://web.fccj.org/~ethall/2045/ch5/pt1871.gif]

[http://www.dlt.ncssm.edu/TIGER/diagrams/periodic/MendeleevPrediction.gif]

Periodic Table HistoryPeriodic Table History

•Henry Moseley (1913) •Current periodic table which

lists in order of atomic number, from smallest to largest.

The Periodic TableThe Periodic Table

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The Periodic TableThe Periodic Table

The Periodic TableThe Periodic Table

•Periods – Each horizontal row of the periodic table.

[http://www.chem4kids.com/files/art/elem_pertable3.gif]

The Periodic TableThe Periodic Table•Groups – Each

vertical column of the periodic table, also known as families.

•Elements in a group have similar properties.

[http://www.chem4kids.com/files/art/elem_pertable3.gif]

The Periodic Table & The Periodic Table & ElectronsElectrons

•The shape of the periodic table is due to where the electrons are located in an atom.

[http://www.bpc.edu/mathscience/chemistry/images/periodic_table_of_elements.jpg]

Nothing here???

The Periodic Table & The Periodic Table & ElectronsElectrons

•“Blocks” of the periodic table represent the last type of cloud that electrons occupy.

[http://wps.prenhall.com/wps/media/objects/476/488316/Instructor_Resources/Chapter_09/FG09_17.JPG]

“S” Cloud

[http://wps.prenhall.com/wps/media/objects/476/488316/Instructor_Resources/Chapter_09/FG09_29.JPG]

“S” Cloud

“P” Clouds

The Periodic Table & The Periodic Table & ElectronsElectrons

•Electron Configurations show where electrons are located in an atom.

•Example: H is 1s1

Period #

Cloud Type

# of Electrons

The Periodic Table & The Periodic Table & ElectronsElectrons

[http://wps.prenhall.com/wps/media/objects/476/488316/Instructor_Resources/Chapter_09/FG09_28.JPG]

Example: Oxygen 1s2 2s2 2p4 (e- = 8)

[http://wps.prenhall.com/wps/media/objects/476/488316/Instructor_Resources/Chapter_09/FG09_28.JPG]

Example: Magnesium 1s2 2s2 2p6 3s2 (e- = 12)

The Periodic Table & The Periodic Table & ElectronsElectrons

•Valence Electrons are the “outside” electrons in an atom

•Highest period number = Highest energy level

The Periodic Table & The Periodic Table & ElectronsElectrons

• Or you could look at the group number…

• Silicon has 4 valence electrons

The Periodic Table & The Periodic Table & ElectronsElectrons