Chapter 5

The Periodic Table

Overview

The Language of The Language of ChemistryChemistryThe Language of The Language of ChemistryChemistry

• The elements, The elements, their names, their names, and symbols and symbols are given on are given on thethe PERIODIC PERIODIC TABLETABLE

• How many How many elements are elements are there?there?

Overview

The Periodic TableThe Periodic Table

Dmitri Mendeleev (1834 - 1907)Dmitri Mendeleev (1834 - 1907)

See Pages 132 & 133See Pages 132 & 133

Glenn Glenn SeaborgSeaborg

(1912-1999 )(1912-1999 )• Discovered 8 Discovered 8

new elements.new elements.

• Only living Only living person for person for whom an whom an element was element was named.named.

PeriodsPeriods in the Periodic in the Periodic TableTable

Overview

GroupsGroups in the Periodic in the Periodic TableTable

Elements in groups react in similar ways!

Overview

Regions of the Periodic Regions of the Periodic TableTable

Overview

End of Overview

The Periodic TableThe Periodic Table

Dmitri Mendeleev (1834 - 1907)Dmitri Mendeleev (1834 - 1907)

See Pages 132 & 133See Pages 132 & 133

The Periodic TableThe Periodic Table Organizing Anything

• Classification is arranging items into groups or categories according to some criteria.

• The act of classifying creates a pattern that helps you recognize and understand the surroundings.

5.1

The Periodic TableThe Periodic Table Organizing the ElementsOrganizing the Elements

• Can be arranged by atomic number or atomic mass.

• 1, 2, 3, 4, 5, 6, etc.

• 1.008, 4.003, 6.941, etc.

• Can be arranged by physical or chemical properties.

• Radius of atom, ionization potential etc.

Organizing the ElementsOrganizing the Elements

• The atomic mass is usually placed under the symbol for the atom.

• The periodic table is arranged by atomic number: 1, 2, 3, 4, etc., with new rows placed when there is a big change in a property.

C6

Atomic Number

12.0

Atomic MassC6

12Atomic Number

Mass Number

• Gave us a functional scheme with which to classify elements.–Mendeleev’s scheme was based on

chemical properties and the mass of the elements.

– It was noticed that the chemical properties of elements increased in a periodic manner.

–He used the table to predict the occurrence and chemical properties of elements which had not yet been discovered.

Organizing The Organizing The Elements by Dmitri Elements by Dmitri

MendeleevMendeleev

Mendeleev’s Periodic Table

• He left blank spaces in his table when the properties of the elements above and below did not seem to match.

• Mendeleev used the properties of existing elements to predict properties of undiscovered elements.

Mendeleev’s Periodic Table

• He used Eka and the name of an known element. (eka-aluminum)

– Properties like aluminum

• He predicted the properties based on the known elements properties.

• When the unknown elements were discovered, it was found that Mendeleev had closely predicted the properties of the elements as well as their discovery. (This showed the usefulness of his table)

Mendeleev’s Table of Elements (1872)

Section 5.1

a. Mendeleev arranged the elements in order of increasing mass so that elements with similar properties were in the same column.

Section 5.1

b. Mendeleev used the properties of existing elements to predict properties of undiscovered elements.

Section 5.1

C. The close match between Mendeleev’s predictions and the actual properties of new elements showed how useful his periodic table could be.

Other Periodic TablesSome periodic tables that look quite different from the one in your book. Look at Theodore Benfey’s version of a periodic table, which he made in 1960.

The Modern Periodic TableThe Modern Periodic Table

• The periodic table is made up of rows of elements and columns.

• An element is identified by its chemical symbol.

• The number above the symbol is the atomic number

• The number below the symbol is the atomic mass of the element.

• A row is called a period

• A column is called a family

5.2

• (A) Periods of the periodic table

• (B) families of the periodic table

Periodic LawPeriodic Law

• When elements are arranged in

order of increasing atomic #,

elements with similar properties

appear at regular intervals.

5.2

Metals, Nonmetals, Metalloids

• The broken line represents the boundary between metals and nonmetals.

• To the right of the broken line, nonmetals.

• To the left of the broken line, metals.

• Next to the broken line on the right are the metalloids.

Metals

• Found to the left of the “diagonal line”• lose electrons in chemical reactions• A metal has the following properties.

»Metallic luster»High heat and electrical conductivity.»Malleability, able to be rolled or

pounded into a thin sheet.»Ductile, can be pulled into a wire. »Form alloys (solid-solution of one

metal in another)

5.2

Transition ElementsTransition ElementsTransition ElementsTransition Elements

Lanthanides and actinidesLanthanides and actinides

Iron in air gives Iron in air gives iron(III) oxideiron(III) oxide

The Transition Elements

An important use of transition elements is as pigments in paints and glasses

Nonmetals

• Found to the right of the “diagonal line”• Like to gain electrons from metals, or

share electrons among themselves• A nonmetal has the following properties

»No metallic luster»Poor conductor of heat and

electricity.»When it is a solid it is brittle so it

cannot be pounded or pulled into a wire.

5.2

Metalloids

• Elements next to the “diagonal line” or dividing line between metals and nonmetals

• B, Si, Ge, As, Sb, and Te

• Physical properties of a metal (can be “convinced” to conduct electricity) and chemical properties of a nonmetal

5.2

5.3 Representative Groups

Chemical Families

• The first 2 chemical families of the periodic table:

– the alkali metals (IA)

–the alkaline earth metals (IIA)

Group 1A: Alkali MetalsGroup 1A: Alkali MetalsGroup 1A: Alkali MetalsGroup 1A: Alkali Metals

Cutting sodium metalCutting sodium metal

Reaction of potassium + H2O

Group IA - The Alkali Metals(Li, Na, K, Rb, Cs, Fr)

• Alkali metals because they react with water to from an alkaline solution

• Lose 1 valence electron

• Highly reactive

Reaction of potassium + H2O

MagnesiumMagnesium

Magnesium Magnesium oxideoxide

Group 2A: Alkaline Earth MetalsGroup 2A: Alkaline Earth Metals

Group IIA - The Alkaline Earth Metals (Be, Mg, Ca, Sr, Ba, Ra)

• Not as reactive as Group IA

• Are soft metals like Earth

• Lose 2 valence electrons

• Also react with H2O but less violently

Ca(s) + 2H2O(l) Ca(OH)2(aq) + H2(g)

Group IIA - The Alkaline Earth Metals (Be, Mg, Ca, Sr, Ba, Ra)

Various forms of CaCO3

• Reaction of magnesium with oxygen Mg(s) + O2(g) MgO(s)

Group IIA - The Alkaline Earth Metals (Be, Mg, Ca, Sr, Ba, Ra)

flashbulbs

Other Group/Families

• Four group/families of the periodic table:

–Boron (IIIA)

–Carbon (IVA)

–Nitrogen (V)

–Oxygen (VIA)

Group IIIA - The Boron Family(B, Al, Ga, In, Tl)

• Boron is mined in the form of Borax, and is used in laundry soap

• Laboratory glassware contains borosilicates

• Aluminum metal is the most abundant metal in the earth’s crust and has many uses

Group IIIA - The Boron Family(B, Al, Ga, In, Tl)

• Gallium Arsenide is used in the manufacture of computer chips

Group IIIA - The Boron Family(B, Al, Ga, In, Tl)

Group IVA - The Carbon Family(C, Si, Ge, Sn, Pb)

• Carbon is essential for life and is found in all organic molecules

Group IVA - The Carbon Family(C, Si, Ge, Sn, Pb)

• Carbon is found in different structures or ALLOTROPES - graphite, one of the softest substances known, and diamond, the hardest

Group IVA - The Carbon Family(C, Si, Ge, Sn, Pb)

Quartz or SiO2

Elemental Si is used in the semiconductor industry

Group VA - The Nitrogen Family(N, P, As, Sb, Bi)

A control rocket on the Space Shuttle uses hydrazine, N2H4, as fuel

There are two varieties of P, red and white.

Group VIA - The Oxygen Family(O, S, Se, Te, Po)

Stratospheric ozone shields us from harmful UV radiation. Ozone is destroyed by Cl-

containing molecules used in refrigeration

The ozone “hole” over Antarctica

Chemical Families

• The last 2 chemical families of the periodic table:

–halogens (VII) –the noble gases (VIIIA)

Group 7A: The Halogens Group 7A: The Halogens (salt makers) (salt makers) F, Cl, Br, I, AtF, Cl, Br, I, At

Group 7A: The Halogens Group 7A: The Halogens (salt makers) (salt makers) F, Cl, Br, I, AtF, Cl, Br, I, At

Group VIIA - The Halogens(F, Cl, Br, I, At)

• Halogens need only one electron to fill their outer shell

• They are very reactive.

Br2 and I2

Group VIIA - The Halogens(F, Cl, Br, I, At)

Halogen mean “salt-former”. Here sodium metal reacts vigorously with Cl2(g)

Group 8A: The Noble Group 8A: The Noble (Inert) Gases(Inert) Gases

He, Ne, Ar, Kr, Xe, RnHe, Ne, Ar, Kr, Xe, Rn

Group 8A: The Noble Group 8A: The Noble (Inert) Gases(Inert) Gases

He, Ne, Ar, Kr, Xe, RnHe, Ne, Ar, Kr, Xe, Rn• Lighter than air

balloons

• “Neon” signs

• Very Unreactive because they have full electron levels

XeOFXeOF44XeOFXeOF44

Group VIIIA - The Noble (Inert) GasesHe, Ne, Ar, Kr, Xe

• Noble gases have completely filled outer shells

• They are almost non reactive.

Neon lamp

Group VIIIA - The Noble (Inert) GasesHe, Ne, Ar, Kr, Xe

Helium-Neon lasers

5.3