Transcript Chapter6

Pre-class Activity 12/18
How are
library books
classified?
Why is such a
classification
system
valuable?
History of the Periodic Table
 John Newlands (1864)
 Recognized that when
atoms are arranged by
increasing mass, their
properties repeated
every eighth element
which he named the “law
of octaves”
 Elements with similar
properties were arranged
in the same row
 Did not work for all
known elements
 Dimitri Mendeleev (1869)
 Organized the first
periodic table
 Arranged elements by
increasing atomic mass
 Was able to predict the
existence and properties
of yet undiscovered
elements
Modern Day Periodic Table
Henry Moseley
o Arranged elements according to
increasing atomic number instead of
increasing atomic mass
o Demonstrated a periodic repetition of
chemical and physical properties called
the periodic law
Pre-class Activity 1/5
What is the location, by group and period, of
Boron?
Group 13 Period 2
Which element is found in group 9, period 5?
Rhodium
Organization of the Periodic Table
Group
Period
Main Group or Representative Group
Elements
p-block
s-block
Transition Elements
d-block
f-block
Metals, Metalloids, and Nonmetals
Metalloids
Metals
Transition Metals
Inner Transition Metals
Properties of Metals
Shiny
Smooth
Solid at room temp
Malleable
Ductible
Conduct Electricity
Metalloids (Semimetals)
Metalloids contain
physical and
chemical properties
of both metals and
non-metals
13
14
15
16
17
B
C
N
O
F
Boron
Carbon
Nitrogen
Oxygen
Fluorine
Al
Si
P
S
Cl
Aluminium
Silicon
Phosphorus
Sulfur
Chlorine
Ga
Ge
As
Se
Br
Gallium
Germanium
Arsenic
Selenium
Bromine
In
Sn
Sb
Te
I
Indium
Tin
Antimony
Tellurium
Iodine
Tl
Pb
Bi
Po
At
Thallium
Lead
Bismuth
Polonium
Astatine
Nonmetals
Nonmetals are generally gases
or brittle, dull-looking solids.
They are poor conductors of
electricity.
classification of Elements
s block
p block
1
d block
2
3
4
5
3
4
6
5
7
6
4
5
f block
Pre-class Questions 1/7
How many valence electrons does Antimony
(Sb) have? What is it’s Lewis Dot structure?
5
Sb
Which element is represented by the
following electron configuration?
[Xe] 6s24f143d8
Platinum (Pt)
Periodic Trends in Atomic Radii
Decreases
Increases
From one group to the next, atomic radius decreases because the the
electrostatic attraction between increasingly larger nuclei increases,
pulling the electrons closer to the nucleus
From one row to the next, atomic radius increases because increasing
numbers of neutrons shield the electrostatic force and valence electrons
are located further and further away from the nucleus
Periodic Trends in Ionic Radii
Increases
Increases
Decreases
For positive ions, charge numbers increase as more electrons are lost from the
atom. The electrostatic force is greater for smaller numbers of electrons which
decreases the ionic radius.
For negative ions, as the charge number increases, so does the number of
electrons. Electrostatic forces decrease and the ionic radius increases in size.
From one row to the next, atomic radius increases because increasing numbers
of neutrons shield the electrostatic force and valence electrons are located
further and further away from the nucleus
Periodic Trends in Ionization Energy
The amount of energy required to remove an electron from an atom
Increase
Decrease
Increased nuclear charge that occurs from one group to the next
accounts for electrons being held more tightly within the atom. The
more tightly they are held, the greater the amount of energy that is
required to remove and electron from an atom.
From one row to the next, ionization energy increases because increasing
numbers of neutrons shield the electrostatic force and valence electrons
are located further and further away from the nucleus
Periodic Trends in Electronegativity
Ability of an atom to attract electrons
Increase
Decrease