Transcript For Regular: Chapter 5 Notes

The Periodic Table
Chapter 5
When the Elements Were Discovered
8.1
Development of the Periodic
Table
• Mendeleev listed the elements in several vertical
columns in order of increasing atomic mass.
• He noticed a regular reoccurrence in their
properties.
• This was the beginning of the first periodic table.
• In 1913, Moseley, determined the atomic number
and added those.
Modern Periodic Table
• Horizontal rows are called
periods.
• Periodic Law: When elements
are arranged in order of
increasing atomic number, there
is a periodic pattern in their
physical and chemical
properties.
Electron Configurations
• Noble gases – elements in which
the outtermost s and p sublevels
are full.
• Representative elements –
elements whose outtermost s or p
sublevels are only partially filled.
..more
• Transition metals – elements whose
outermost s sublevel and the nearby d
sublevel contains electrons.
• Inner transition – elements whose
outermost s sublevel and the nearby f
sublevel generally contain electrons.
ns2np6
ns2np5
ns2np4
ns2np3
ns2np2
ns2np1
d10
d5
d1
ns2
ns1
Ground State Electron Configurations of the Elements
4f
5f
8.2
Classification of the Elements
8.2
8.3
8.3
Atomic Radii
8.3
8.3
Cation is always smaller than atom from
which it is formed.
Anion is always larger than atom from
which it is formed.
8.3
8.3
Chemistry in Action: The 3rd Liquid Element?
113 elements, 2 are liquids at 250C – Br2 and Hg
223Fr,
t1/2 = 21 minutes
Liquid?
Ionization energy is the minimum energy required to
remove an electron from a gaseous atom in its ground state.
I1 + X (g)
X+(g) + e-
I1 first ionization energy
I2 + X (g)
X2+(g) + e-
I2 second ionization energy
I3 + X (g)
X3+(g) + e-
I3 third ionization energy
I1 < I2 < I3
8.4
8.4
Filled n=1 shell
Filled n=2 shell
Filled n=3 shell
Filled n=4 shell
Filled n=5 shell
8.4
General Trend in First Ionization Energies
Increasing First Ionization Energy
Increasing First Ionization Energy
8.4
Electron affinity is the negative of the energy change that
occurs when an electron is accepted by an atom in the
gaseous state to form an anion.
X (g) + e-
X-(g)
F (g) + e-
X-(g)
EA = +328 kJ/mol
O (g) + e-
O-(g)
EA = +141 kJ/mol
8.5
8.5
8.5
Electronegativity
• Electronegativity – the tendency
for an atom to attract electrons to
itself when I is chemically
combined with another element.
• Going down a group decreases
electronegativity, while moving
from left to right in a period
increases it.
Chemistry in Action: Discovery of the Noble Gases
Sir William Ramsay