Download The Periodic Table - Newburyport High School

The Periodicities of the
Periodic Table
Ionization energy
• energy needed to make an ion by losing
electrons
First Ionization Energy
• Definition:
– energy needed to remove the most
loosely held e-
Valence electron
high E electron
Outermost electron
1st
Why 1st? Is there a 2nd?
• 2nd ionization energy
–Energy needed to remove the
second electron
• 3rd ionization energy
–Energy needed to remove the
third electron
1st
3rd e- removed
2nd e- removed
What’s holding the e- in
place?
• PROTONS
• “Opposites attract”
• There is a force of attraction
between protons (+) and
electrons (-)
Ionization E trend?
• As move across a period…IE increases.
WHY?
3 p+
9 p+
• As you go across a period
–a proton and an electron are
being added
– more p+ hold the e- tighter
when in the same energy
level
• Increasing nuclear charge
• As move UP a group … IE increases.
WHY?
Period 1
More E to remove
Period 2
Period 3
Period 4
Let’s figure it out . . .
Potassium
19 p+
Sodium
11 p+
Lithium
3 p+
INCREASES because
...
• As you go up a group
–the electron shells get closer
to the nucleus and can hold
on to the e- tighter.
–ALSO………………….
Potassium
19 p+
SHIELDING
• as you go DOWN a group
– Not only does the distance increase
between the p+ and valence e•
e- in outer shells
repel each other &
makes them easier to
remove
Who has the highest IEs?
Lowest?
Electronegativity
E-neg
Electronegativity
• Ability of an atom to attract electrons of
other atoms.
• In other words. . .
– Atoms with high e-neg are bullies that
steal electrons
Electronegativity
• Periodic trend
F
INCREASES
EXCEPT for Noble gases. WHY?
Already have full valence shell!
Summary
Atoms with
high electronegativities
also have
high ionization E
Atomic Radius
• Radius
–distance from the center of a
circle (Nucleus) to the outermost
edge (valence shell)
R
Atomic Radius Periodicity
D
E
C
R
E
A
S
E
S
DECREASES
Why?????
• Why does atomic radius DECREASE
as you move up a group?
• Losing full Energy levels
• Why does atomic radius DECREASE
as you move across a period?
• Increasing the # of p+ holds the ein tighter
NOW Compare
• the radii of Na0 and Na+
• POSITIVE Ionic radius is
smaller
• the radii of Cl0 and Cl• NEGATIVE Ionic radius is
larger
Compare 2 different
elements
• Compare the ionic radius of Mg2+
and the atomic radius of Ne.
The ionic radius of Mg2+ is smaller
than the atomic radius of Ne
because the Mg 2+ ion has more
p+ (12) than the Ne atom (10).
General Formulas of
compounds
• You can look at the groups on the
periodic table and determine how they
will combine with elements of different
groups.
• Group 1 Group 2 Group16 Group 17
• +1
+2
-2
-1
1:1
General Formula: AB
• Group 1 Group 2 Group16 Group 17
• +1
+2
-2
-1
1:1
General Formula: AB
• Group 1 Group 2 Group16 Group 17
• +1
+2
-2
-1
2:1
General Formula:
A2B
• Group 1 Group 2 Group16 Group 17
• +1
+2
-2
-1
1:2
General Formula:
AB2
THE END