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ENGAGE:

The Element Song 1955

Click above!

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Patterns and Trends

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1

2 13 15 16 1718

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3 5 6 7 8 9 104 11 12

The Group Numbers on top for columns of “families.”

Group numbers are also related to the number of valence electrons.

This is group 1 the alkali group.

Families have similarbut not identical characteristics

This is group 1 the alkali group.

Families have similarbut not identical characteristics

Increasing Atomic mass going down a group

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4

3

5

6

7

1

2

Periods numbered down the side

and form rows or “periods.”

This is period number 3

which means it has3 energy levels.

This is period number 3

which means it has3 energy levels.

Increasing Atomic mass going across a period.

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• Consider a simple diatomic molecule.

• The distance between the two nuclei is called the bond distance.

• If the two atoms which make up the molecule are the same, then half the bond distance is called the covalent radius of the atom.

Sizes of Atoms and IonsSizes of Atoms and Ions

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Periodic Trends in Atomic Radii• down a group, the atoms become larger.

• across a period, atoms become smaller.

Larger radius

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Energy Level 3: Na, Mg, Al, Si, P, S Cl & Ar

Periods represent the number of rings or what scientists call “energy levels” of electrons.

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Metals, Nonmetals, and MetalloidsMetals, Nonmetals, and Metalloids

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What type of elements are these?

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Metals, Nonmetals, and Metals, Nonmetals, and MetalloidsMetalloids

Metals• Metallic character refers to the properties of metals

(shiny or lustrous, malleable and ductile, oxides form basic ionic solids, and tend to form cations in aqueous solution).

• Metallic character increases down a group.• Metallic character decreases across a period.• Metals give up electrons easily, forming positive ions.

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Fr

Au

Al

Pt

React lose electrons to nonmetals; become a positive ion (cation)

Au, Pt: Are exceptions they are very unreactive!

e-

e-

e- e-

+

e-

e-

++

++

+

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Fr

Au

Al

Pt

Melting and boiling points

Increase temperature of MP and BP

Incr

ease

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What type of elements are these?

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React Gain electrons from metals; become a negative ion (anion),

or share with nonmetals.

e-

e- e- e-

e- e- e-

e- e-

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Melting and boiling points

Increase Temperature of MP & BP.

Increase

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What type of elements are these?

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React Gain or Lose electrons; become a

cation or anion.

Metalic and nonmetalic properties.

e- + e-

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