The Periodic Table
Mendeleev’s Periodic Table
Rows in order of increasing atomic
mass
 Similar properties in same column
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Periodic Table – an arrangement of
elements in columns based on
properties that repeat row to row
Periodic Law – pattern of repeating
properties in the periodic table
Modern Periodic Table

Elements arranged by increasing protons
Period – rows
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# of orbitals increase
Group / Family – columns
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# of valence e- increase
Similar properties due to # of valence e-
Classes of Elements
Metals – good electrical & heat conductors
 Solid at room temperature
 Malleable, ductile
 Transition metals – group 3-12
 Nonmetals – poor electrical & heat
conductors
 Many are gases at room temperature
 Metalloids – properties between metals &
nonmetals
 Conduction varies with temperature

Variation Across a Period
From left to right
 Elements become less metallic
 Elements become less reactive
 # of valence e- increases
Valence e- - e- in highest energy level
Groups / Families
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Alkali metals – Group 1A
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Alkaline Earth metals – Group 2A
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1 valence eExtremely reactive (especially with 7A)
Found as compounds
Reactivity increases from top to bottom of column
2 valence eHarder than 1A
Reactive (especially with 6A)
Boron Family – Group 3A
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3 valence eie. Al – most abundant metal in Earth’s crust
Groups / Families (cont.)
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Carbon Family – Group 4A
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Nitrogen Family – Group 5A
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4 valence eMetallic nature increases from top to bottom of
column
5 valence e-
Oxygen Family – Group 6A
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6 valence eie. Oxygen – most abundant element in Earth’s
crust
Groups / Families (cont.)
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Halogen Family – Group 7A
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Noble Gas Family – Group 8A
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7 valence eHighly reactive
Reactivity decreases from top to bottom
8 valence e- (full outer shell)
He is full with 2eColorless, odorless
Extremely unreactive
Rare Earth metals - Lanthanide &
Actinide Series
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Located at bottom of table
Noble Gases
Halogen Family
Oxygen Family
Rare Earth Metals
Nitrogen Family
Carbon Family
Boron Family
Alkaline Earth Metals
Alkali Metals
Transition Metals
Works Cited
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www.sof.edu