The Periodic TableThe Periodic Table

Unit II—Part 4Unit II—Part 4

Adapted by NCDPI – Unit 2 Matter all around usAdapted by NCDPI – Unit 2 Matter all around us

The Father of the Periodic TableThe Father of the Periodic Table—Dimitri Mendeleev—Dimitri Mendeleev

Mendeleev was the first scientist to notice Mendeleev was the first scientist to notice the relationship between the elementsthe relationship between the elements Arranged his periodic table by atomic massArranged his periodic table by atomic mass Said properties of unknown elements could be Said properties of unknown elements could be

predicted by the properties of elements around predicted by the properties of elements around the missing elementthe missing element

Image taken from:

http://jscms.jrn.columbia.edu/cns/2006-04-18/fido-luxuriantflowinghair/mendeleev

Henry MoseleyHenry Moseley

Moseley later discovered that the Moseley later discovered that the periodic nature of the elements was periodic nature of the elements was associated with atomic number, not associated with atomic number, not atomic massatomic mass

Image taken from: Image taken from: http://dewey.library.upenn.edu/sceti/smith/

The Periodic TableThe Periodic Table

Column = Group or Family

18 columns on the Periodic Table

Row = Period

7 rows on the Periodic Table

PeriodsPeriods•Each row is called a “period”•The elements in each period havethe same number of energy levels

1st Period = 1 E. Level2nd Period = 2 E. Levels3rd Period = 3 E. Levels4th Period = 4 E. Levels5th Period = 5 E. Levels6th Period = 6 E. Levels7th Period = 7 E. Levels

Middle School ScienceImage: Chem4kids.com

GroupsGroups•Each column is called a “group”•Each element in a group has the same number of electronsin their outermost energy level (valence electrons)Group 1 = 1 electron Group 2 = 2 electrons

Except for He, ithas 2 electrons4

Group 8 =8 electrons

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Metals, Nonmetals, and Metals, Nonmetals, and Semi-metalsSemi-metals

Metals are to the left of the stair-

step

Onlynonmetal on

the metal sideNonmetals are on the right of the stair-step

Semi-metals,

“metalloids,”

touch the stair-step

Special Rows on the PTSpecial Rows on the PT

Lanthanides

Actinides

What does the information in What does the information in the box tell me?the box tell me?

11

HH1.0081.008

Atomic Number = # of protons

Atomic Mass = # of

protons plus neutrons

Elemental Symbol

The Groups of the Periodic The Groups of the Periodic TableTable Group 1: The Alkali MetalsGroup 1: The Alkali Metals

Most reactive metals on the PTMost reactive metals on the PT Rarely found free in natureRarely found free in nature Charge of 1—1 valence electronCharge of 1—1 valence electron

87

Fr(223)

55

Cs132.905

37

Rb85.468

19

K39.098

11

Na22.990

3

Li6.941

1

H1.008

++ +

+++

++ ++

-

-

-

-

--

-

- +

-

-

-

The Groups of the Periodic The Groups of the Periodic TableTable

Group 2: The Alkaline Earth MetalsGroup 2: The Alkaline Earth MetalsStill quite reactiveStill quite reactiveCharge of 2—2 valence electronsCharge of 2—2 valence electrons

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Image: http://wildeboer-fitch.wikispaces.com/2008fall+CalciumImage: http://wildeboer-fitch.wikispaces.com/2008fall+Calcium

T he Groups of the Periodic T he Groups of the Periodic TableTable

Groups 3-12: Transition MetalsGroups 3-12: Transition MetalsFound freely and in compounds in natureFound freely and in compounds in natureCharge is usually 2 but can vary—usually Charge is usually 2 but can vary—usually

2 valence electrons2 valence electrons

Group 13: Boron FamilyGroup 13: Boron FamilyCharge is 3—3 valence electronsCharge is 3—3 valence electrons

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The Groups of the Periodic The Groups of the Periodic TableTable

Group 14: The Carbon FamilyGroup 14: The Carbon FamilyContains elements that can form Contains elements that can form

unusual bonds (carbon and silicon)unusual bonds (carbon and silicon)Charge is +4 or -4—contains 4 valence Charge is +4 or -4—contains 4 valence

electronselectrons

Group 15: The Nitrogen FamilyGroup 15: The Nitrogen FamilyCharge is -3—contains 5 valence Charge is -3—contains 5 valence

electronselectrons

The Groups of the Periodic The Groups of the Periodic TableTable Group 16: The Oxygen Family Group 16: The Oxygen Family

Also known as the chalcogensAlso known as the chalcogens Charge is -2 has 6 valence electronsCharge is -2 has 6 valence electrons

Group 17: The HalogensGroup 17: The Halogens Most reactive nonmetalsMost reactive nonmetals charge is -1 has 7 valence electronscharge is -1 has 7 valence electrons

Group 18: The Noble Gases (The Inert Group 18: The Noble Gases (The Inert Gases)Gases) Nonreactive Nonreactive Charge is 0—2 or 8 valence electronsCharge is 0—2 or 8 valence electrons

https://www.google.come/search?q=valence+electrons+periodic+tablehttps://www.google.come/search?q=valence+electrons+periodic+table