Download The Periodic Table Trends

The Periodic
Table Trends
They Might Be Giants - Meet the Elements
Element Funkiness
Daniel Radcliffe - Element Song
Here are some chemistry jokes
with elements as punch-lines
I apologize for them ahead of time
What did the silver atom
say to get the gold
atom’s attention?
Au
There is more to the
periodic table than just
what can be found in
the element boxes.
The periodic table is organized
by
increasing atomic number
and
elements with similar properties
& same valence electrons are
placed together in a column
The periodic table of elements
• Is organized to maximize trends
• Can be used to predict the properties
of undiscovered or unfamiliar elements
• Can predict reactions between
elements without actually doing the
experiment.
Trends we will study




Atomic Mass
Atomic Number
State of Matter
Metallic Character

Valence Electrons &
Bonding

Electronegativity

Atomic Radius


Ionization Energy
Reactivity
Some Trends in
Depth
Valence Electron Trend
What are Valence Electrons?
Valence electrons are
electrons in the last & highest
electron energy level.
1?
Valence shell
electron pattern
Why are Valence
Electrons Important??
When atoms get close to each other, the
nucleus of one atom will interact with the
other atom’s valence electrons. A chemical
reaction and bond can result from that interaction.
9+
9+
Valence Electrons are
Importance because….
chemical reactions are just a
rearranging of valence electrons &
valence electrons are the cause of
bonding (ionic, covalent, metallic)
Valence electrons are rearranged in
chemical reactions so atoms complete
their valence level of electrons.
Bonding also results from atoms
completing their valence shell.
When Atoms react and bond
valence electrons are
transferred or shared.
How the Periodic
Table can be used
to Predict Bonding
• Metallic – Two Metal Atoms (both
atoms would like to lose valence
electrons)
• Covalent – Two Nonmetals (both
atoms would like to gain
electrons)
• Ionic – Metal and Nonmetal
(metal atom would like to lose
electrons and nonmetal would
like to gain electrons)
Ionic Bonds
• A metal atom Loses electron(s)
& a nonmetal Gains electron(s)
Sodium and Chlorine Video
Ionic bonds are created by
attraction between oppositely
charged atoms / particles.
Covalent Bonds
• Sharing of electrons between
two nonmetals
• If two atoms need electrons to
complete their valence shell
they make covalent bonds.
Nonmetals need electrons.
Metallic Bonds
• Sharing electrons b/w two metals
both of which want to lose electrons
Quiz – Valence Electrons & Bonds
1. What are valence electrons?
2. What is the pattern for increasing
valence electrons?
3. Why are valence electrons
important?
Quiz – Valence Electrons & Bonds
Type of Bond
What combo of
elements make
the bond?
Describe the role
of electrons in
the bond
Bond type can more accurately be
predicted with ELECTRONEGATIVITY
Electronegativity
• Electronegativity is the ability of an atom to
attract electrons from another atom.
Value of Electronegativity
•0
no attraction for more e
• 4 great attraction for
e
The absolute difference of two
elements electronegativities will
tell whether the bond will be
covalent or ionic
Calculating Bond Character
• Absolute difference b/w the electronegativities
determines type of bond
Metallic:
Two Metals
Nonpolar Covalent: 0 ≤ X ≤ 0.4
Polar Covalent:
0.4 < X ≤1.7
Ionic:
X > 1.7
There is no firm cut-off between
Ionic and Covalent it is gradual
and continuous transition.
Increasing electronegativity difference
+
-
+
-
Fluorine Video –
University of Nottingham
Atomic Radius
Atomic radius (volume) is how far the
outside electrons are from the nucleus.
Depends on:
•The strength of attraction between the
electrons & nucleus (atomic number)
•The number energy levels
Adding Electron Energy Levels
Increases Atomic Radius
• Each new energy level occupies a
larger more distant region around the
nucleus.
2s
1s
1s
Contraction Along a Period
Adding more protons without adding an
energy level contracts atomic radius. The
greater positive charge in the nucleus the
stronger the pull the nucleus has on the
electrons within the existing energy level.
Atomic Radius
Atomic Radius increases to the left (fewer
p+) and down (new energy levels). The
largest radius is bottom left corner (Fr).
NI3 Demo
Which is more stable
NH3 and NI3?
IONIZATION ENERGY
Ionization energy is the energy
needed to remove an electron
from an atom or ion
(ionization always requires energy)
Energy + X (g) 
+
X
+
(g)
e
Ionization Energy
• The stronger the nuclear
charge (more protons) and
smaller atoms (electrons
are closer to nucleus) the
I.E. is higher
• IE is highest for He and lowest for Fr
st
1
Ionization Energies
Ionization Energy
increases to the right
and up
Reactivity
Metal element
reactivity increases
Nonmetal element
reactivity increases
Give an Explanation of Metal and
Nonmetal Reactivity using Atomic
Radius and Atomic Number (or
Ionization Energy)
END
Good videos from University of
Nottingham,
Mg Video
Ag Video
When atoms complete their
valence energy level they
lower their potential energy
Two atoms go to an
ice cream shop………
Electron Affinity
e
+ X (g) 
X
(g)
Electron Affinity
• Electron affinity measures
energy lost or gained
when adding an electron.
Sign of Electron Affinity Values
• While IEs are all positive, some
electron affinities are negative.
• Negative values indicate that energy
is lost by the atom when it gains an
electron.
C4.9 Introduced: X
I can state the Periodic Law and give it
as the organizing principle for the
periodic table.
Outermost (valence)
energy level is the skin
of the atom
Gain or Loss of Electrons?
Positive ions are formed by
metal elements. They lose
electrons because that is a less
energetic pathway.
Nonmetals make negative
ions….