Transcript Chapter 10 Atomic Theory and the Periodic Table

10.4 Energy Levels of
Electrons
• Electrons move in definite energy levels;
these are labeled 1 - 7
• Each level has sublevel(s) which are
probability shapes that show where the
electrons may be at any one time. Also
known as orbitals.
• S orbital can hold up to 2 electrons (0, 1, 2)
• p orbital can hold up to 6 electrons (0-6)
• d orbital can hold up to 10 electrons (0-10)
• f orbital can hold up to 14 electrons (0-14)
• Aufbau chart shows how electrons fill into
the main energy levels and the sublevels or
orbitals
Energy Levels and
Sublevels
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1s
2s
3s
4s
5s
6s
7s
2p
3p
4p
5p
6p
7p
3d
4d
5d
6d
7d
4f
5f
6f
7f
Aufbau Diagram or
Chart
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1s
2s
3s
4s
5s
6s
7s
START HERE and follow
2p
the arrows!
3p 3d
4p 4d 4f
5p 5d 5f
6p 6d 6f
7p 7d 7f
Electron Configuration
• 4 Be
• 1s2 2s2
• 15 P
• 1s22s22p63s23p3
• 25 Mn
• 1s22s22p63s23p64s23d5
Pauli Exclusion Principle
• Pauli exclusion principle states
that no more than 2 electrons
can be in the same suborbital.
Even so, this would cause them
to have precisely the same
quantum address. So Pauli
decided there has to be a way
to tell one electron from
another. In other words, they
must differ by at least one
quantum number!
Pauli Exclusion Principle
• So they invented spin (+1/2
or -1/2) called spin up and
spin down. Has nothing to
do with the direction of the
electron--we don’ t know
how they move just where
they may be at with 90%
chance of finding it inside
the energy level and orbital
designated.
Hund’s Rule
• Hund’s rule states that
electrons fill unpaired
until there is no more
room then they will
pair (applies to p, d and
f orbitals)
Orbital Diagrams
S orbitals get one box
P orbitals get 3 boxes (2 e- per
box)
D orbitals get 5 boxes and f gets
7
Orbital Diagrams (cont.)
• Insert electrons (using arrows
into each box according to
Hund’s and Pauli)
2 p3
Answer
• 2p3 (arrows can all point up or
down)
• Now try 4f10
Answer to
10
4f
• Arrows may point up or down if
they are in boxes individually;
however, if there are 2
electrons in a box, one must
point up and one down.
Electrons and the
Periodic Table Revisited
History of the Table
Periodic Law
Important People
Mendeleev
• Mendeleev was a Russian
chemist who arranged the
known elements in vertical
columns in order of increasing
mass and noticed a pattern in
physical and chemical
properties
Mosley
• Mosley was a British physicist
who determined the atomic
number (number of protons) of
the atoms of elements and then
arranged the elements
according to their atomic
number.
Periods and Groups
• Periods of the periodic table are
the rows across
• Groups or Families are columns on
the periodic table.
• Currently we have 18 groups. We
will use the 1-18 designations not
the A/B or Roman Numerals
Areas of the Periodic
Table
• Representative elements
or Main Group are those
that are in Groups 1, 2, 13,
14, 15, 16, 17, 18
• Transition elements are
Groups 3 - 12 , also called
the Heavy Metals
Inner Transition
• Rare Earth elements that are
located in the bottom two rows
(away from the rest of the table)
of the periodic table
Main
group
Periodic Table
GROUP NUMBERS
1
2
3
Heavy Metals or
Transition elements
4
5
6
7
Period
Numbers
Inner Transition Elements
Main Group or
Representative
elements
Groups with names
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Group
Group
Group
Group
1 = Alkali Metals
2 = Alkaline Earth Metals
18 = Inert or Noble Gases
17 = Halogens
Periodic Table and
Electron Configuration
• The light metals compose the s
block.
• The transition elements are the
d block.
• The nonmetals are p block.
• The inner transition (rare earth)
metals are the f block.
Periodic Table
1
2
3
4
3
4
5
4
5
6
5
6
7
6
7
4f
5f
s block
p block
d block
f block
Noble (inert) gases
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Complete the electron
configurations for the
Noble Gases (Hint:
Group 18)
• Xe =
He
1s2
Ne
1s22s22p6
Ar =
1s22s22p63s23p6
Kr =
1s22s22p63s23p64s23d1
04p6
1s22s22p63s23p64s23d10
4p65s24d105p6
• Rn =
1s22s22p63s23p64s23d10
4p65s24d105p66s24f145d1
06p6 Except He, do you
see a trend in all of the
noble gas
configurations?
• What do they all end
in?
Shorthand Notation
• We use the noble gases in
shorthand notation
• Find the closest noble gas that
has an atomic number LESS
than that of the element
Example
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Ex. K
What is K’s atomic number?
19
Closest noble gas?
Ar
What is Ar’s atomic number?
18 = 1s22s22p63s23p6
= [Ar] 4s1 = Means the first 18 electrons are
arranged like argon and the last electron
is called the VALENCE ELECTRON
(outermost shell)
Example for you to try
•You try Ba
2
•Ba = [Xe] 6s
•Try Pb
•Pb = [Xe] 6s24f145d106p2