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Atomic Structure
Schrödinger equation has approximate solutions for multielectron atoms, which indicate that all atoms are like hydrogen
Atomic Structure
3s
3p
2s
2p
3d
Energy
Energy
Schrödinger equation has approximate solutions for multielectron atoms, which indicate that all atoms are like hydrogen
3s
3p
2s
2p
3d
1s
1s
hydrogen
multi-electron
Atomic Structure
• orbitals are populated by electrons according to certain rules
Additional quantum number!
! spin quantum number (ms)
spin -1/2
spin +1/2
Atomic Structure
• orbitals are populated by electrons according to certain rules
Name
Symbol
Permitted Values
Property
Principal
n
1, 2, 3, etc
orbital size (energy)
Angular Momentum
l
0 to n-1
orbital shape
Magnetic
ml
-l to 0 to +l
orbital orientation
Spin
ms
+1/2 or –1/2
direction of e- spin
Atomic Structure
• orbitals are populated by electrons according to certain rules
exclusion principle: no two electrons in the same atom
can have the same four quantum numbers
Atomic Structure
exclusion principle: no two electrons in the same atom
can have the same four quantum numbers
an orbital
electrons
Atomic Structure
exclusion principle: no two electrons in the same atom
can have the same four quantum numbers
empty
an orbital
electrons
Atomic Structure
exclusion principle: no two electrons in the same atom
can have the same four quantum numbers
empty
an orbital
electrons
one electron
Atomic Structure
exclusion principle: no two electrons in the same atom
can have the same four quantum numbers
empty
an orbital
one electron
two electron
electrons
only three options!
Atomic Structure
• orbitals are populated by electrons according to certain rules
exclusion principle: no two electrons in the same atom
can have the same four quantum numbers
n=4
Electron Shielding Effects:
different levels
n=1
lower Eionization
higher Eionization
Electron Shielding Effects
inner shells
n=2
lower Eionization
higher Eionization
Electron Shielding Effects:
same orbital
2+
2+
He+
He
lower Eionization
higher Eionization
2+
2+
He+
He2+
Energy Profile of Sublevels
>f>d>p>s
l=3
l=2
l=1
l=0
Energy Profile of Sublevels
E
N
E
R
G
Y
1s
Energy Profile of Sublevels
E
N
E
R
G
Y
2p
2s
Hund’s rule: maximum
number of unpaired electrons
for the same sublevel (n, l)
1s
Energy Profile of Sublevels
E
N
E
R
G
Y
3s
3p
2p
2s
1s
Energy Profile of Sublevels
E
N
E
R
G
Y
3d
3s
2p
2s
1s
3p
4s
4p
Types of Electrons
! inner (core) electrons: those in the previous
noble gas
! outer electrons: after that highest energy levels
! valence electrons: same as outer, involved in
forming chemical bonds
Practice Problems
8.44. One reason spectroscopists study excited states is to
gain information about the energies of orbitals that are
unoccupied in an atom’s ground state. Each of the
following electron configurations represent an atom in an
excited state. Identify the element and write its condensed
ground-state configuration.
(a) 1s22s22p63s1
(b) 1s22s22p63s23p64s23d44p1
(c) 1s22s22p63s23p44s1
(d) 1s22s22p53s1
Trends in Periodic Table
metallic behavior increases
ionization energy decreases
Trends in Periodic Table
Non-metallic behavior increases
electron affinity increases
Practice Problems
8.68. Which element would you expect to be more metallic?
(a) Ca or Rb
(b) Mg or Ra
(c) Br or I
(d) Si or P
I or Se?
Practice Problems
Sample 8.6. Using condensed electron configurations,
write reactions for the formation of the following
elements:
(a) Iodine (Z=53)
(b) Potassium (Z=19)
(c) Indium (Z=49)