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Isotope Formulas_ Quantum Numbers _amp; Electron Configurations

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Isotope Formulas_ Quantum Numbers _amp; Electron Configurations Powered By Docstoc
					Isotope Formulae,
Quantum Numbers
    & Electron
  Configurations

  …pretty lofty stuff
    Isotope Formulae
• Provide element’s symbol
• Mass number
 – mass# = #p+ + #n
 – written as a superscript to the left
• Atomic number
 – atomic# = #p+ or #e-
 – written as a subscript to the left
       Isotope Formulae
                 Mass#
               Atomic#
                       X
Carbon has two naturally occurring isotopes:
carbon-12 and carbon-13

     12                       13
       6
        C                       6
                                 C
        Isotope Formulae
Give the isotope formula for each of the
following:
                                 3
1. Hydrogen with 2 neutrons
                                  1
                                   H
                                18
2. Fluorine with 9 neutrons
                                  9
                                    F
                             235
3. Uranium with 143 neutrons
                              92
                                U
  Valence Electron(s)
• The electron(s) farthest from
  the nucleus or in the outermost
  energy level.
    Aufbau Principle
• Comes from German word
  meaning “to build”
• Electrons will occupy lower
  energy orbitals first
      Pauli Exclusion
         Principle
• An atomic orbital can hold at
  most two electrons.
• If an atomic orbital holds two
  electrons, they must have
  opposite spins.
        Hund’s Rule
• When filling atomic orbitals of
  equal energy, place electrons
  with parallel spins in the
  orbitals first. Then, place the
  oppositely spinning electrons
  in to the orbitals.
   Quantum Numbers
• Similar to your address
• Describe where electrons live
  within an atom
• Four quantum numbers for
  every electron of every atom
   Quantum Numbers
• Principal (n)
  – Describes the energy level in
    which the electron lives
  – May be any positive integer
  – Thus, 1, 2, 3, etc.
    Quantum Numbers
• Azimuthal or angular mometum (l )
 – Azimuth means course or bearing
 – Describes the shape of the pathway
   that the electron takes or the shape of
   the atomic orbital
 – May be any integer from zero to (n-
   1)…it’s dependent on “n”
 – Thus, when n=1, l can only be 0
     Quantum Numbers
• Magnetic (ml )
 – Describes the orientation of the
   atomic orbital in 3-D space
 – May range from -l to +l …it’s
   dependent on “l” which is dependent
   on “n”
 – Thus, when n=1, l can only be 0, and
   ml can only be 0
 – When n=2, l can be 0 or 1, and when
   l is 1, ml can be –1, 0, or +1…or
   three places in space
     Quantum Numbers
• Spin (ms )
  – Describes the spin of the electron
  – May be either –½or +½, it’s
    dependent upon none of the other
    quantum numbers
  – Thus, when n=1, l can only be 0, and
    ml can only be 0, but ms can be
    either –½or +½
                    The Quantum Numbers



      name                symbol                  values


Principal Quantum                          any positive integer
                            n
     Number                                 from 1 to infinity


Azimuthal Quantum            l            any integer from 0 to n-
     Number                                          1


Magnetic Quantum            ml            any integer from -l to +l
    Number


  Spin Quantum
                            ms                   - ½ or + ½
     Number
    Quantum Numbers
• What are the four quantum
  numbers of hydrogen’s electron?

 n=1
 l=0
 ml = 0
 ms = –½
      Quantum Numbers
• What are the four quantum
  numbers of all of boron’s five
  electrons?
n=1       n=1       n=2       n=2       n=2
l=0       l=0       l=0       l=0       l=1
ml = 0    ml = 0    ml = 0    ml = 0    ml = -1
ms = –½   ms = +½   ms = -½   ms = +½   ms = -½
    Quantum Numbers
• What are the four quantum
  numbers of sodium’s valence
  electron?
 n=3
 l=0
 ml = 0
 ms = –½
Electron Configurations
• Also describe where electrons
  live within an atom
• It’s like a translation of
  quantum numbers.
• They give the energy level,
  atomic orbital, and number of
  electrons residing in the
  orbital and energy level.
Electron Configurations
• Energy level
 – May be any positive integer
 – Just like the principal quantum
   number
Electron Configurations
• Atomic Orbital or Sublevel
 – Represented by letters: s, p, d, f
 – Translates azimuthal number
   and magnetic number
 – s is the same as l = 0
 – p is the same as l = 1
 – d is the same as l = 2
 – f is the same as l = 3
Electron Configurations
• Number of Electrons
 – in either an atomic orbital or a
   sublevel
 – max of 2 in the s sublevel
 – max of 6 in the p sublevel
 – max of 10 in the d sublevel
 – max of 14 in the f sublevel
Electron Configurations
• Use the periodic table to guide
  you in writing electron
  configurations.
• Find the link between 2,6,10,
  and 14 and the periodic table.
 Electron Configurations
• What are the four quantum numbers of
  hydrogen’s electron? What is the
  electron configuration of hydrogen?
                                       # of
 n=1           energy
                         1s 1       electrons
                level
 l=0
 ml = 0                 sublevel/
                         orbital
 ms = –½
 Electron Configurations
• Write the e- configurations of the
  next 9 elements (through Ne).
 He…1s2

 Li…   1s22s1     Look at the sum
                  of the superscripts…
 Be… 1s22s2

 B… 1s22s22p1
Electron Configurations
C…  1s22s22p2

N… 1s22s22p3
O… 1s22s22p4
F… 1s22s22p5

Ne…1s22s22p6
 Electron Configurations
• Shorthand configurations are
  written by assuming that you can
  let the symbol of the noble gas
  preceding the valence electrons
  represent the e- configuration to
  that point.
Electron Configurations
      …shorthand
He…1s2
Li… [He]2s1
Be… [He]2s2
B… [He]2s 22p1

C… [He]2s 22p2
Electron Configurations
      …shorthand
N… [He]2s22p3
O… [He] 2s22p4
F… [He] 2s22p5

Ne…[He] 2s22p6
Electron Configurations
      …shorthand
Na… [Ne]3s1
Si… [Ne] 3s23p2
Cl… [Ne] 3s23p5

Ar… [Ne] 3s23p6
Electron Configurations
      …shorthand
Ca…[Ar]4s2
Sc… [Ar] 4s23d1
Mn…[Ar] 4s 23d5

Se… [Ar] 4s23d104p4
Electron Configurations
      …shorthand
I… [Kr] 5s24d105p5
La… [Xe] 6s25d1
Ce…[Xe] 6s 25d14f1

Hg…[Xe] 6s24f145d10
  Exceptional Electron
Configurations…shorthand
Cr… [Ar] 4s23d4 [Ar] 4s13d5
Cu…[Ar] 4s23d9 [Ar] 4s13d10
Mo…[Kr] 5s 24d4 [Kr] 5s14d5

Ag…[Kr] 5s24d9 [Kr] 5s14d10
      Orbital Diagrams
• Show the electron configuration
  while illustrating the Aufbau
  Principle, Pauli Exclusion
  Principle, and Hund’s Rule
• Place energy on the y-axis
• Use lines to represent orbitals
• Use up and down arrows to
  indicate spin
Orbital Diagrams (template)
    3px   3py   3pz

    3s

E   2px   2py   2pz

    2s

    1s
    Orbital Diagram for H
     3px   3py   3pz

     3s

E    2px   2py   2pz

     2s

     1s
    Orbital Diagram for He
     3px   3py   3pz

     3s

E    2px   2py   2pz

     2s

     1s
    Orbital Diagram for Be
     3px   3py   3pz

     3s

E    2px   2py   2pz

     2s

     1s
    Orbital Diagram for C
     3px   3py   3pz

     3s

E    2px   2py   2pz

     2s

     1s
    Orbital Diagram for O
     3px   3py   3pz

     3s

E    2px   2py   2pz

     2s

     1s
    Orbital Diagram for P
    3px   3py   3pz

    3s

E   2px   2py   2pz

    2s

    1s
          Wrap-Up
• Write the 4 quantum numbers for
  each of nitrogen’s 7 electrons.
• Write the electron configuration
  for nitrogen.
• Write the orbital diagram for
  nitrogen.

				
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