The Periodic Table

History

Memorize the periodic table by Monday

History of the periodic table

Newlsands

John Newlands (1837, English) Law of Octaves (every 8th element was

grouped together) Ordered elements by atomic mass

Mendeleev

Dmitri Mendeleev (1869, Russian) Also organized elements

by increasing atomic mass.

Elements with similar properties were grouped together.

Mendeleev

Dmitri Mendeleev (1869, Russian) Predicted properties of undiscovered

elements.

Moseley

Henry Mosely (1913, British)

Organized elements by increasing atomic number.

Resolved discrepancies in Mendeleev’s arrangement.

This is the way the current Periodic Table is arranged.

Organization of theElements

The Periodic Table

MetalsNonmetalsMetalloids

Metallic Character

Metals

Most of the periodic table is made of metals!

Form positive ions Metals are good conductors of

heat and electricity Metals are malleable Metals are ductile Metals have high tensile

strength Metals have luster

Examples of MetalsExamples of Metals

Potassium, K reacts with water and must be stored in kerosene

Zinc, Zn, is more stable than potassium

Copper, Cu, is a relatively soft metal, and a very good electrical conductor.

Mercury, Hg, is the only metal that exists as a liquid at room temperature

PropertiesProperties of Nonmetalsof Nonmetals

Nonmetals are poor conductors of heat and electricity Nonmetals tend to be brittle Many nonmetals are gases at room temperature

Examples of NonmetalsExamples of Nonmetals

Sulfur, S, was once known as “brimstone”

Microspheres of phosphorus, P, a reactive nonmetal

Graphite is not the only pure form of carbon, C. Diamond is also carbon; the color comes from impurities caught within the crystal structure

PropertiesProperties of of MetalloidsMetalloids

Metalloids straddle the border between metals and nonmetals on the periodic table.

They have properties of both metals and nonmetals.Metalloids are more brittle than metals, less brittle than most nonmetallic solids Metalloids are semiconductors of electricity Some metalloids possess metallic luster

Silicon, Si – A MetalloidSilicon, Si – A Metalloid

Silicon has metallic luster Silicon is brittle like a nonmetal Silicon is a semiconductor of electricity

Other metalloids include: Boron, B Germanium, Ge Arsenic, As Antimony, Sb Tellurium, Te

Metals vs. Nonmetals

Metals Nonmetals

Luster High-shiny Dull

Conductor Good for heat and electricity poor

Malleable Yes-hammered into sheets No-brittle

Ductile Yes-pulled into wires No-brittle

Melting point High Low

Density High low

Chemical Reactivity

Families Similar valence e- within a group result in

similar chemical properties

Chemical Reactivity

Alkali MetalsAlkaline Earth MetalsTransition MetalsHalogensNoble Gases

Periodic Trends

The Periodic Table

0

50

100

150

200

250

0 5 10 15 20Atomic Number

Ato

mic

Ra

diu

s (

pm

)

Periodic Law

When elements are arranged in order of

increasing atomic #, elements with similar

properties appear at regular intervals.

0

50

100

150

200

250

0 5 10 15 20Atomic Number

Ato

mic

Ra

diu

s (

pm

)

Atomic Radius size of atom

© 1998 LOGALFirst Ionization Energy

Energy required to remove one e- from a neutral atom.

© 1998 LOGAL

Melting/Boiling Point

Other Properties

Atomic Radius

0

50

100

150

200

250

0 5 10 15 20Atomic Number

Ato

mic

Ra

diu

s (

pm

)

Atomic Radius

Li

ArNe

KNa

1

2

3

4 5

6

7

Atomic Radius Increases to the LEFT and DOWN

Atomic Radius

Why larger going down?

Higher energy levels have larger orbitals

Shielding - core e- block the attraction between the nucleus and the valence e-

Why smaller to the right?

Increased nuclear charge without additional shielding pulls e- in tighter

Atomic Radius

First Ionization Energy

0

500

1000

1500

2000

2500

0 5 10 15 20Atomic Number

1s

t Io

niz

ati

on

En

erg

y (k

J)

Ionization Energy

KNaLi

Ar

NeHe

1

2

3

4 5

6

7

First Ionization Energy Increases UP and to the RIGHT

Ionization Energy

Why opposite of atomic radius?

In small atoms, e- are close to the nucleus where the attraction is stronger

Why small jumps within each group?

Stable e- configurations don’t want to lose e-

Ionization Energy

Successive Ionization Energies

Mg 1st I.E. 736 kJ

2nd I.E. 1,445 kJ

Core e- 3rd I.E. 7,730 kJ

Large jump in I.E. occurs when a CORE e- is removed.

Ionization Energy

Al 1st I.E. 577 kJ

2nd I.E. 1,815 kJ

3rd I.E. 2,740 kJ

Core e- 4th I.E. 11,600 kJ

Successive Ionization Energies

Large jump in I.E. occurs when a CORE e- is removed.

Ionization Energy

1

2

3

4 5

6

7

Melting/Boiling Point Highest in the middle of a period.

Melting/Boiling Point

Ionic Radius

Cations (+)

lose e-

smaller

© 2002 Prentice-Hall, Inc.

Anions (–)

gain e-

larger

Ionic Radius

Which atom has the larger radius?

Be or Ba

Ca or Br

Ba

Ca

Examples

Which atom has the higher 1st I.E.?

N or Bi

Ba or Ne

N

Ne

Examples

Which atom has the higher melting/boiling point?

Li or C

Cr or Kr

C

Cr

Examples

Which particle has the larger radius?

S or S2-

Al or Al3+

S2-

Al

Examples

Chinese Periodic Table

Periodic TableHydrogen: most abundant gas in the universe, 1 valence electron, often exists as a single proton.

Alkali Metals: 1 valence electron, forms +1 ion, most reactive metals, combine with halogens to form salts. Soft silvery white. Most reactive is at the bottom.

Alkaline Earth Metals: 2 valence electrons, +2 ion

Transition Metals: multiple charges, bright colored, used in building, coins, and jewelry

Halogens: “Salt formers”, 7 valence electrons, -1 ion, most reactive nonmetals

Noble Gases: all have full valence shell of 8 electrons, except He which has 2. Inert (unreactive) gases.

Rare Earth or Inner Transition Metals:

Many synthetic, rare, or radioactive elements. Divided into Lanthanides and Actinides