Download The Periodic Table

The Periodic Table
Chapter 6
Developing the Periodic
Table p46
Warm up: why are tables useful to us?
 In the early 1800s, scientists began to
classify elements.
 German chemist Dobereiner grouped
them into triads of similar properties.
 English chemist Newlands, arranged
them based on mass.

Developing the Periodic
Table p46
Russian chemist, Dimitri Mendeleev,
organized elements based on mass
and properties.
 He found properties of elements
repeat with increasing masses.


His table was accurate and he could
predict properties for elements not
yet discovered. ex. Germanium.
(DON’T WRITE) Germanium is located below
silicon. Mendeleev predicted its properties
based on this location in his table.
Ekasilicon (Es)
Germanium (Ge)
1. Atomic mass: 72
1. Atomic mass: 72.61
2. High melting pt.
2. Melting pt: 945° C
3. Density: 5.5g/cm3
3. Density: 5.323g/cm3
4. Dark gray metal
4. Gray metal
5. Will obtain from
K2EsF6
5. Obtain from K2GeF6
6. Will form EsO2
6. Forms oxide (GeO2)
Modern Periodic Law p50
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
Warm up: explain how
the table reflects
(shows us) the
structure of the atom.
Henry Moseley revised
Mendeleev’s table and
used atomic number
instead of mass.
Periodic law:
properties of elements
are periodic functions
of atomic numbers.
Modern Periodic Table p50



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Rows on the table are called PERIODS
Columns on the table are called GROUPS
or FAMILIES
There are 7 periods and 18 groups.
Electron config. are repeated in periods.
similar e- config. in the same group.
Elements in groups are also listed in
order of their increasing n.
Octet Rule p50
Eight electrons in an outer energy
level make an atom stable. (2 in s
and 6 in the p)
 True for all except He & H
 atoms react with one another to
obtain these 8 valence e-.
 Some atoms gain or lose e- (ions)
and some share e- (molecules).

Periodicity Graphing Activityp49
Use class set of graphs to answer:
1. What happens to the atomic radius as you
move across a period? Down a period?
2. What happens to the valence electrons as
you go across a period? Down a period?

3.
Do properties of elements repeat on
the periodic table? Use CREW.
Periodic Trends p52
Warm up: describe the trend that
our climate is experiencing.
 We can use the Periodic Table to
predict properties of elements

Atomic Radius
(p52)
As energy level increases , the size of
the electron cloud i. Size of atoms
moving down table.
 Atoms by one proton for each element
going across. This pulls the e- cloud in
tighter= atomic radius.
 General rule: atomic size largest at
bottom left corner.

Sketch picture on p51.
 (use ¼ pg)

Trends in Oxidation Numbers
p52
This is the charge an element would
have if it had an octet (8 ve-)
 (talk about valence electrons)
 Remember adding electrons is
negative and removing electrons is
positive.

Oxidation numbers- Look at periodic
table handout. sketch p 51
1+
0
2+
3+
Tend to have more
than one oxidation
number
3+
3+ or 4+
2+
or
4+
3-
2-
1-
Ionization Energy p 52

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The energy required to remove an efrom an atom.
As atoms get closer to an octet, the
harder it is to remove electrons. As
electrons get further from the nucleus,
the easier it is to remove them.
Ionization energy greatest at top
right corner
(LEFT PAGE)
draw on p51
Electronegativity
(p52)
Electronegativity is a measure of an
atom’s attraction for another e-.
 Metals are low.(need to get rid of
extra e-)
 Nonmetals are high.(need more for
octet)
 As atoms get larger, harder to
attract e- because they are further
from nucleus.

Electronegativity

(p51)
Increases across table with the
arrows (draw on pg, ¼ pg)
Organizing Information on
the Periodic Table p54

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Warm up: Explain something new that you
learned about the periodic table.
label the following on your table :
Group 1
Alkali metals
Group 2
Alkaline earth metals
Group 16
Chalcogens
Group 17
Halogens
Group 18
Noble gases
Sc – Uub
Transition metals
La – Lu
Lanthanoids
Inner transition
Ac – Lr
Actinoids
metals
Organizing Information on
the Periodic Table p54
Draw a stair step dark line starting
between B and Al.
 Label the left side: metals
 Label the right side:
nonmetals
 Write METALLOID (semimetal) along
stair step line.

Basic Properties of Metals,
Nonmetals, and Metalloids
Metals:
1. Hard and shiny. Malleable.
2. Conduct heat and electricity well.
 Nonmetals:
1. Generally gases or brittle solids.
2. If solid, dull surface.
3. Good insulators.
 Metalloids:
1. Properties of both metals and non.

Review
When graphed, atomic radii
demonstrates a periodic trend
Ionization Energy

METAL
1. Low 1st ionization
energy.
2. Located on left
side of Periodic
Table.
3. Form positive
ions.(wants to give
up extra e- to have
an octet on previous
energy level)

Nonmetal
1. High 1st
ionization energy.
2. Located on the
right side of
Periodic Table.
3. Form negative
ions.(want to get
more electrons to
get octet)
Multiple Ionization Energies

Additional e- can be lost from an
atom and the ionization energies can
be measured.
IONIZATION ENERGIES (kilojoules per mole)
Element
1st
2nd
3rd
4th
H
1312.0
He
2372.3
5220
Li
520.2
7300
11750
Be
899.5
1760
14850
20900
B
800.6
2420
3660
25020
5th
32660
In Summary
Periodic table is a chart of elements
in which the elements are arranged
based on their e- configurations
which dictates their properties.
 Moving down a group in the periodic
table, atomic radii becomes larger
because more energy levels are
needed for more e-.

In Summary
As the size becomes larger, the eare located farther away from the
positive center.
 This decreases the affinity of that
atom to hold on to these outer e-,
thus decreasing e- affinity.
 Ionization energy is low because it is
easy for the atom to lose these
outer e-.

In Summary
Moving across a period in the periodic
table, atomic radii becomes smaller
because the energy levels of periods
are the same but the positive centers of
atoms increase. This pulls the e- cloud
closer to the nucleus, making the atom
smaller.
 Ionization energy and e- affinity
increases for these smaller atoms.

THE END