Transcript ATOMIC NUMBER!!!

THE
PERIODIC
TABLE
PERIODIC
When something
occurs at regular
intervals
(you can predict what
happens / comes next)
So what makes the
periodic table periodic?
ATOMIC
NUMBER!!!
(across the chart)
PERIODIC LAW
The properties of the
elements are a
periodic function of
their atomic numbers
PERIOD
All of the elements
in a horizontal
row
GROUP
All of the elements
in a vertical
column
(aka Family)
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
ALKALI METALS
1
s
group
• Good Conductors
ALKALINE EARTH
METALS
2
s
group
• Harder, more dense,
stronger than alkali
TRANSITION
METALS
d sub energy level
• Columns 3-12
LANTHANOID
SERIES
4f sub energy level
• Z = 57-70
ACTINOID
SERIES
5f sub energy level
• 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)
HALOGENS
5
p
group
• Combine with metals
to form salts
• Very reactive
NOBLE GASES
6
p
group
• 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
OCTET
The eight outer
electrons in an
atom
FACT:
Atoms with full outer
energy levels are very
stable (less reactive)
OCTET RULE
If an atom has 8
electrons in its outer
energy level, it is
unreactive (save He)
Pretend we had a subenergy 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]
1
10
4s 3d …why???
The atom is more
stable if it has a full
“d” sub-energy level
and a ½ full “s” subenergy level
Check out the PT on
page 392-393.
Look at Gd. What is
the e configuration?
[Xe]
2
7
1
6s 4f 5d …why???
To Review…How do we make
sub energy levels more stable?
Move electrons so SUBENERGY 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)
WHITEBOARDING
Write the electron
configuration for Copper
WHITEBOARDING
Identify all of the elements
with deviations in their
electron configurations
WHITEBOARDING
Write the old “normal”
electron configuration for
Mo, Au, La, Cm. Below
each of these write the
electron configuration
with deviation.