Electrons In Atoms

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Electrons In Atoms

• Electron Configurations

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Electrons

• They are only one of three fundamental subatomic
  particles.
• The have very little mass in comparison to
  protons and neutrons.
• They move rapidly about the nucleus in a volume
  that defines the size of the atom.

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Modern Models of the Atom
In the modern atomic model, electrons can be
found only in certain energy levels, not between
levels. Furthermore, the location of electrons
cannot be predicted precisely.
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A quantized property is a property that can have
only certain values, that is, not all values are
allowed.
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Electron Shells An electron shell is a region of
space about a nucleus that contains electrons
that have approximately the same energy and that
spend most of their time approximately the same
distance from the nucleus.
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Imagine that the nucleus is in a deep basement.
The energy levels begin on the first floor, above
the basement. Electrons can be on any floor, but
they cannot be between floors. Electrons gain
energy by riding up the elevator and lose energy
by riding down.
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Electron Shells A shell number, n, is used to
identify each electron shell.
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Electron Shells Shell electron capacity 2n2,
where n shell number
Shell Number Designation (n) Electron Capacity (2n2)
1st 1 2 X 12 2
2nd 2 2 X 22 8
3rd 3 2 X 32 18
4th 4 2 X 42 32
5th 5 2 X 52 50
6th 6 2 X 62 72
7th 7 2 X 72 98
The maximum number of electrons in this shell
has never been attained in any element now know.
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Electron subshells
An electron subshell is a region of space within
an electron shell that contains electrons that
have the same energy.
Number of subshells in a shell n. Where n
shell number
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Electron subshells
Subshells are identified by a number and a
letter. The number indicates the shell to which
the subshell belongs. The letter are s, p, d, or
f.
These subshells can be further subdivided into
orbitals, and each orbital is a distinct region
of space that can contain a maximum of two
electrons.
Shells ? Subshells ? Orbitals
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Electron Orbitals
A electron orbital is a region of space within an
electron subshell where an electron with a
specific energy is most likely to be found.
Shells ? Subshells ? Orbitals
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There are four kinds of orbitals s, p, d, and f
orbitals.
Movie
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Orbitals There are multiple electron orbitals
within an atom. Each has their own energy level
associated to them, and their own properties.
Because each orbital is different, we assign them
specific quantum numbers  1s, 2s, 2p 3s, 3p,4s,
3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d,
7p.
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..
4f (14 e)
Shell 4
4 Subshells
4d (10 e)
4p (6 e)
4s (2 e)
3d (10 e)
Shell 3
3 Subshells
3p (6 e)
3s (2 e)
Shell 2
2 Subshells
2p (6 e)
2s (2 e)
Shell 1
1 Subshells
1s (2 e)
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subshells in n 4
subshells in n 3
subshells in n 2
f
d
subshells in n 1
d
p
p
p
s
s
s
s
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An electron subshell is an energy sublevel within
an electron shell in which the electrons all have
the same energy.Subshells are identified by a
number and a letter ?
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The electrons of lower energy are held nearer the
nucleus and those of higher energy are farther
away on the outer surface of the atom.
Subshells
Shell Number
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Three main rules for writing electron
configurations.
Pauli Exclusion Principle No two electrons in an
atom have the same four quantum numbers.
Aufbau Principle Orbitals of lowest energy are
filled first.
Hunds Rule Every orbital in a subshell is singly
occupied with one electron before any one orbital
is doubly occupied, and all electrons in singly
occupied orbitals have the same spin.
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Each shell is broken down into subshells (s,p,d,
and f) and each subshell is made up of 1,3, 5, or
7 orbitals, which contain the electrons.
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s holds 2 p holds 6 d holds 10 f holds 14
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1
H
Electron Configuration
1s1
Orbital Diagram
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2
He
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3
Li
1s2
2s1
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Be
Beryllium
1s2
2s2
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B
Boron
1s2
2s2
2p1
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C
Carbon
1s2
2s2
2p2
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Ne
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F
Fluorine
2p5
1s2
2s2
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Na
Sodium
3s1
2p6
1s2
2s2
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Mg
Magnesium
3s2
2p6
1s2
2s2
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Al
Aluminum
3s2
2p6
1s2
2s2
3p1
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I
3s2
2p6
1s2
2s2
4p6
3p6
3d10
4s2
5p5
4d10
5s2
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Using the handout try to write electron
configurations for the following
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Element of e E config. Orbital diagrams Condensed e config.
H 1 1s1 1s1
He 2 1s2 1s2
Li 3 1s2 2s1 He 2s1
Be 4 1s2 2s2 He 2s2
B 5 1s2 2s2 2p1 He 2s2 2p1
C 6 1s2 2s2 2p2 He 2s2 2p2
N 7 1s2 2s2 2p3 He 2s2 2p3
O 8 1s2 2s2 2p4 He 2s2 2p4
F 9 1s2 2s2 2p5 He 2s2 2p5
Ne 10 1s2 2s2 2p6 He 2s2 2p6
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Three main rules for writing electron
configurations.
Pauli Exclusion Principle No two electrons in an
atom have the same four quantum numbers.
Aufbau Principle Orbitals of lowest energy are
filled first.
Hunds Rule Every orbital in a subshell is singly
occupied with one electron before any one orbital
is doubly occupied, and all electrons in singly
occupied orbitals have the same spin.
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Write the electron configuration and orbital
diagram for Sodium. Look on the Periodic Table
for how many electrons it has.
3s1
2p6
1s2
2s2
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Write the electron configuration and orbital
diagram for Magnesium.
3s2
2p6
1s2
2s2
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Write the electron configuration and orbital
diagram for Aluminum.
3s2
2p6
1s2
2s2
3p1
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Write the electron configuration and orbital
diagram for Silicon.
3s2
2p6
1s2
2s2
3p2
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Write the electron configuration and orbital
diagram for P.
3s2
2p6
1s2
2s2
3p3
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Write the electron configuration and orbital
diagram for S.
3s2
2p6
1s2
2s2
3p4
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Write the electron configuration and orbital
diagram for Sn.
3s2
2p6
1s2
2s2
4p6
3p6
3d10
4s2
5p2
4d10
5s2
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Element of e E config. Orbital diagrams Condensed e config.
Na 11 1s2 2s2 2p6 3s1 Ne 3s1
Mg 12 1s2 2s2 2p6 3s2 Ne 3s2
Al 13 1s2 2s2 2p6 3s2 3p1 Ne 3s2 3p1
Si 14 1s2 2s2 2p6 3s2 3p2 Ne 3s2 3p2
P 15 1s2 2s2 2p6 3s2 3p3 Ne 3s2 3p3
S 16 1s2 2s2 2p6 3s2 3p4 Ne 3s2 3p4
Cl 17 1s2 2s2 2p6 3s2 3p5 Ne 3s2 3p5
Ar 18 1s2 2s2 2p6 3s2 3p6 Ne 3s2 3p6
K 19 1s2 2s2 2p6 3s2 3p6 4s1 Ar4s1
Ca 20 1s2 2s2 2p6 3s2 3p6 4s2 Ar4s2
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Element of e Orbital diagrams Condensed e config.
Sc 21 1s2 2s2 2p6 3s2 3p6 4s2 3d1 Ar 4s23d1
Ti 22 1s2 2s2 2p6 3s2 3p6 4s2 3d2 Ar 4s2 3d2
V 23 1s2 2s2 2p6 3s2 3p6 4s2 3d3 Ar 4s2 3d3
Cr 24 1s2 2s2 2p6 3s2 3p6 4s1 3d5 Ar 4s1 3d5
Mn 25 1s2 2s2 2p6 3s2 3p6 4s2 3d5 Ar 4s2 3d5
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Fe 26 Ar 4s2 3d6
Co 27 Ar 4s2 3d7
Ni 28 Ar 4s2 3d8
Cu 29 Ar 4s1 3d10
Zn 30 Ar 4s2 3d10
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The End
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• Identify each of the following atoms on the basis
  of its electron configuration
• 1s22s22p1
• 1s22s22p5
• Ne 3s2
• Ne 3s23p2
• Ne 3s23p5
• Ar 4s1
• Ar4s23d6