Download The Periodic Table

The Periodic Table
Dimitri Mendeleev
• Russian scientist developed the first
published table in 1869.
• Arranged elements in order of atomic
mass
• Elements with similar properties were
placed in columns
• left spaces for undiscovered elements
Periodic Law
the pattern of the table
• Mendeleev’s table was called a periodic
table because……..
• If the elements were arranged in order
of increasing atomic mass then
elements with similar properties would
show up PERIODICALLY.
Henri Moseley (1914)
• Used X-rays to reveal atomic numbers
of several elements.
• Suggested that the elements should be
arranged in order of atomic number
instead of atomic mass.
– Today that is how it is arranged
Reading the Periodic Table
• Families or Groups
– Up and down
• Numbered 1 to 18
• Elements in groups (families) have
similar characteristics
• Periods
–Across the table 1-7
Classifications of Elements
Metals
Non-metals
Metalloids (semi-metals)
Metals
• Elements to the left of the steps
• except H, Ge & Sb
Ge
Metals
Sb
Metal characteristics
• Solids at STP (except mercury)
• good conductors of electricity and heat
– Mobile electrons
•
•
•
•
shiny luster
ductile - drawn (made) into wire
malleable - hammered into sheets
when combined in compound have a
positive oxidation state (+, cation)
• Metallic character increases R to L
– Most reactive metals found in Group
1
Non-metals
18
H
B
Si
As
Te
Non-metal characteristics
•
•
•
•
•
Solid, liquid or gas at STP
used as insulators
solids are dull
brittle
when combined in a compound have
negative oxidation state (-, anion)
• Metallic character decreases L to R
Metalloids
• a.k.a.
Semimetals
• both metal
and non-metal
properties
• “sit on the
steps”
• 2 hide
underneath
B
Si
Ge As
Sb Te
Elements are (s), (l) & (g)
• Solid
– particles have vibratory motion and are tightly
packed
–
Almost ALL of the elements
• Liquid
– particles can move throughout substance
– particles are farther apart than in solids
– conforms to shape of container
– ONLY
Hg and Br
• Gas
– molecules in constant, random, straight
line motion
– molecules fill container
– large space between “volumeless”
molecules
– conforms to the shape of the container
– H, N, O, F, Cl and Group 18
Allotropes
• Different forms of an element found
naturally in the same state
– Different molecular structures
Carbon
diamond, coal, graphite
Oxygen
O2 & O3
Diatomic elements
• Elements found bonded to itself
“uncombined”
H
N
• N2 O2 F2 Cl2 Br2 I2 and H2
O
F
Cl
Br
I
Monoatomic elements
• Inert
• Don’t react
or form
compounds
18
He
Valence shell
filled with 2e-
Ne
Ar
Kr
Xe
Rn
Valence
shell
filled
with
8 e-
Valence electrons
• The number of valence electrons
correspond to group number
• 1, 2 , 13 - 18
Last digit
• The Energy Level (shell) they are in is
the same as the period #
Group / Family Characteristics
Each group has characteristic
properties that are directly related
to electron configuration &
especially the number of valence
electrons
Group 1
•
•
•
•
Alkali Metals
all elements except hydrogen
most reactive metal group
SO reactive they are never found alone
in nature
– always bonded to another element
• form +1 ions
Group 2
• Alkaline Earth Metals
• second most reactive metals group
• SO reactive they don’t occur alone in
nature
– always bonded to another element
• form +2 ions
d- block elements
• Transition Metals
COLORful
ions and solutions
• Transition metals not as reactive as
other metals
• some found in free state
– Au, Ag, Pt
• multiple positive oxidation states
– Iron (IV) oxide FeO2
– Iron (II) oxide FeO
Group 17
• Halogens
• Most reactive nonmetal group
• SO reactive that they don’t occur by
themselves in nature
– at least bonded to themselves (diatomic)
• form -1 ions
Group 18
• Noble gases
• “Inert” gases
• don’t like to combine with other
elements
– Valence shells filled
Ionization Energy
Ionization Energy (first)
• Definition:
– energy needed to remove the most loosely
held eValence electron
high E electron
Outermost electron
What’s holding the e- in
place?
• Nuclear charge
– There is a force of attraction between
protons (+) in the nucleus and electrons () in the orbitals
– “Opposites attract”
Ionization energy
• Hint: energy needed to make an ion by
losing electrons
MOST elements want 8 e(octet rule)
• Elements with only a few valence
electrons will tend to have lower
ionization E
• In other words…
Metals
– It doesn’t take a lot of E to remove their e-
MOST elements want 8 e(octet rule)
• Elements with almost 8 valence
electrons won’t give them up so easy
– It takes a lot of E to remove their e-
• Non-metals have high Ionization E
Who has the highest IEs?
Graph Ionization Energies
• Label X axis with Atomic #1-20
• Label y axis with 1st IE (KJ/mol atoms)
• AFTER you plot the points
– Label data points with element symbols
– Connect data points of same period only
– Separate your graph into Periods
He
Period 1
Period 2
Period 3
Period 4
First Ionization Energy (KJ / mol)
Ne
Ar
H
Ca
Li
Na
What is the periodic trend
for ionization energy?
INCREASES
Ionization E trend?
• As move across a period…IE increases.
WHY?
3 p+
9 p+
• As you go across a period
– a large proton and a tiny electron are
being added.
– more p+ hold the e- tighter
• As move UP a group … IE increases.
WHY?
Period 1
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 valence shell gets closer to the
nucleus and can hold on to the etighter.
SHIELDING
• Reason why IE decreases as you
go down a group
• the distance increases between the p+
and valence e– AND
• e- in outer shells repel each other
–WHICH IS WHY low IE are so
reactive!
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 Graph
Fluorine
Electronegativity
• Determine the periodic trend
F
INCREASES
EXCEPT for Noble gases. WHY?
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 layers of e• Why does atomic radius DECREASE as you
move across a period?
• Increasing the # of p+ holds the e- in tighter
• Increasing NUCLEAR CHARGE
• What happens to atomic radius as you
create a + ion?
• radius decreases
• What happens to atomic radius as you
create a - ion?
• radius increases
• Compare the ionic radus of Mg2+ and
the atomic radius of Ne.
The radius of the Mg2+ ion is smaller
than the atom of Ne, because the Mg2+
ion has more p+ (12) than the Ne atom
(10).
Compare . . .
• Fluoride ion & Fluorine atom
• Sodium ion & Sodium atom
• Fluoride ion & Neon atom
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.
Write these formulas
•
•
•
•
•
•
lithium fluoride
• What do you notice?
sodium fluoride
potassium fluoride • Write the general
formula for Group 1
lithium chloride
and
Group
17
sodium chloride
elements
potassium chloride
AB
Write these formulas
•
•
•
•
•
•
beryllium fluoride
magnesium fluoride
calcium fluoride
beryllium chloride
magnesium chloride
calcium chloride
• What do you notice?
• Write the general
formula for Group 2
and Group 17
elements
AB2
Write these formulas
•
•
•
•
•
•
lithium oxide
sodium oxide
potassium oxide
lithium sulfide
sodium sulfide
potassium sulfide
• What do you notice?
• Write the general
formula for Group 1
and Group 16
elements
A 2B
Write these formulas
•
•
•
•
•
•
beryllium oxide
magnesium oxide
calcium oxide
beryllium sulfide
magnesium sulfide
calcium sulfide
• What do you notice?
• Write the general
formula for Group 2
and Group 16
elements
AB
Formula Writing & Naming
Review
•
•
•
•
•
•
•
Lead IV oxide
Phosphorus pentoxide
SO3
Oxygen
Argon
Aluminum oxide
NiO
Different Forms of the
Periodic Table
• Changes were made to Mendeleev’s
table to look like the modern Periodic
table we use today.
• This is not the only form of the
periodic table that exists, however it
is the most widely accepted.
Stowe’s Physicists p.t.
Benfey p.t.
Zmaczynski p.t.
Alexander Arrangement p.t.
立体周期表の組み立て方 p.t.
THE END