THE PERIODIC TABLE. When something occurs at regular intervals (you can predict what happens / comes next) PERIODIC.

THE PERIODIC

TABLE

When something occurs at regular

intervals(you can predict what happens / comes next)

PERIODIC

So what makes the periodic table periodic?

ATOMIC NUMBER!!!

(across the chart)

The properties of the elements are a

periodic function of their atomic numbers

PERIODIC LAW

.

All of the elements in a horizontal

row

PERIOD

All of the elements in a vertical

column(aka Family)

GROUP

Dmitri Mendeleev (1834-1907)

invented the periodic table based on

increasing atomic mass…and yes, he too, is your friend

Henry Moseley (1913)

revised the periodic table based on

properties and atomic number

…and yes, he too, is your friend

s1 groupALKALI METALS

• Good Conductors

s2 group

ALKALINE EARTH METALS

• Harder, more dense, stronger than alkali

d sub energy level

TRANSITION METALS

• Columns 3-12

4f sub energy level

LANTHANOID SERIES

• Z = 57-70

5f sub energy level

ACTINOID SERIES

• Z = 89-102• All have radioactive forms (unstable p+ & N°)

Columns 13, 14, 15, 16 are

named by the first element in the

column(e.g. Boron Group)

p5 groupHALOGENS

• Combine with metals to form salts

• Very reactive

p6 groupNOBLE GASES

• Inert gases (not reactive)• 8 valence electrons

Classifications by e- Configuration

• Noble Gases: p6

• Representative Elements: s or p (not p6)

• Transition Metals: “d-block”

• Inner Transition Metals: “f-block”

Stability of e-

configurations

The eight outer electrons in an

atom

OCTET

FACT:Atoms with full outer energy levels are very stable (less reactive)

If an atom has 8 electrons in its outer

energy level, it is unreactive (save He)

OCTET RULE

Pretend we had a sub-energy level with 8 electrons. When would it be most

stable?(The egg carton example)

FACT #2:Atoms with filled,

half filled, or empty sub-energy levels are slightly more stable

Check out PT on pages 392-393.

Look at Cu. What is the e- configuration?

[Ar] 4s13d10…why???

The atom is more stable if it has a full “d” sub-energy level and a ½ full “s” sub-

energy level

Check out the PT on page 392-393.

Look at Gd. What is the e- configuration?

[Xe] 6s24f75d1…why???

To Review…How do we make sub energy levels more stable?

Move electrons so SUB-ENERGY levels are FULL,

HALF FULL, or COMPLETELY EMPTY

Now…how do we make ENERGY LEVELS more

stable?

Ways to make full outer energy levels:

•Add electrons to a partially filled outer energy level•Lose all electrons in the outer energy level•Share electrons with another atom

Periodic Trends

ATOMIC RADIUS

The distance from the center of the nucleus

to the outermost energy level

The atomic radius INCREASES

within a family

(just adding energy levels)

The atomic radius DECREASES

within a period

(more positive charge pulling e-)

SHIELDING EFFECT

The positive pull is less because the distance between nucleus and electrons is greater

IONIZATION ENERGY

the energy required to remove an electron

from an atom

The ionization energy DECREASES as you

go down a family

(shielding effect)

The ionization energy

INCREASES across a period

(more p+ have more pull on e-)

ELECTRON AFFINITY

how much an atom desires another

electron

The electron affinity DECREASES as you

go down a family

(shielding effect)

The electron affinity INCREASES across a period

(except for the noble gases)

(more p+ have more pull on e-)

ELECTRONEGATIVITY

The tendency of an atom to attract electrons to

itself when it is bonded to another atom

The electronegativity DECREASES as you

go down a family

(shielding effect)

The electronegativity INCREASES across a

period

(more p+ have more pull on e-)