I II III

I. Periodic Trends

The Periodic Table

0

50

100

150

200

250

0 5 10 15 20Atomic Number

Ato

mic

Ra

diu

s (

pm

)

A. Chemical Reactivity

Families Similar valence e- within a group result in

similar chemical properties

A. Chemical Reactivity

Alkali MetalsAlkaline Earth MetalsTransition MetalsHalogensNoble Gases

Atomic Radius size of atom

© 1998 LOGAL

© 1998 LOGAL

B. Other Properties

Atomic Radius

0

50

100

150

200

250

0 5 10 15 20Atomic Number

Ato

mic

Ra

diu

s (

pm

)

C. Atomic Radius

Li

ArNe

KNa

1

2

3

4 5

6

7

Atomic Radius Increases going DOWN a group Why? Increased number of energy levels

C. Atomic Radius

C. Atomic Radius

1

2

3

4 5

6

7

Decreases moving from left to right across a period.

Why? Increased effective nuclear charge Greater attraction between valence

electrons and protons in the nucleus

As you move across a period,

the number of valence

electrons and the number of

protons increases

Therefore, there is a stronger

attraction!

D. Ionization Energy

First Ionization Energy Energy required to remove one e- from

an atom.

H(g) → H+(g) + e- ∆Ho = -1312.0 kJ/mol

He(g) → He+(g) + e- ∆Ho = 2372.3 kJ/mol

Li(g) → Li+(g) + e- ∆Ho = 572.3 kJ/mol

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)

D. Ionization Energy

KNaLi

Ar

NeHe

1

2

3

4 5

6

7

First Ionization Energy Increases UP and to the RIGHT

E. Ionization Energy

Why? Moving up a column there is a stronger attraction between the electrons and the nucleus

Moving across a period, there is also increased attraction between the electrons and the nucleus because decreased atomic size

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.

D. Ionization Energy

Ionic Radius

Cations (+)

lose e-

smaller

© 2002 Prentice-Hall, Inc.

Anions (–)

gain e-

larger

E. Ionic Radius

F. Electronegativity

*The measure of how strongly an atom attracts another atom’s electrons

• Increases from left to right (except for noble gases)

• Increases as you move up a group

1

2

3

4 5

6

7

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 particle has the larger radius?

S or S2-

Al or Al3+

S2-

Al

Examples