Electron configuration and quantum numbers

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2. Anagrams

3. Electron Location

4. Electron Configuration
It is the assignment of all of the electrons
in an atom into specific shells and
subshells
Uses symbols of the orbitals and the
number of electrons (written of
superscripts) that occupy each orbital.

5. 1s
1
subshell
Number of
electrons in
the orbital
Principal energy
level

6. Maximum electrons per subshell
s = 2 e-
p = 6 e-
d = 10 e-
f = 14 e-

8. Exercise
First 10!!

9. Orbital Diagram/ Orbital
Notation
Consists of boxes and arrows that
represent the orbitals and the electrons,
respectively.
The up and down orientations of the
arrows represent the two magnetic spins
of the electrons.

10. Clockwise rotation Counter clockwise
rotation

11. s
p

12. Aufbau Principle
States that electrons should occupy first
the orbitals with lower energy before those
with higher energy.
Example, 1s orbital should be filled first
before the 2s orbital.
4s orbital has lower energy than the 3d
orbital.

13. Pauli exclusion principle
States that no two electrons in an atom can
possess the same set of quantum numbers.
This principle emphasizes the significance of the
spin quantum numbers.
If two electrons in an atom have the same n, l,
and m
l, they should still have different m
s.
One electron must have m
s= -1/2 and the other
should be m
s= +1/2

14. Hund’s rule of maximum
multiplicity
Suggests that the most stable
arrangement of electrons in subshells is
the one with the greatest number of
parallel spins.
This means that each orbital in a subshell
is singly occupied before pairing of
electrons occurs.

15. Exercise
First 10!!

16. Quiz!!

17. Quiz # 6 (1/2 crosswise)
Write the electron
configuration and draw the
orbital diagram of the elements
with atomic number 21 to 25.

18. Louis de Broglie
Initially thought that electrons behave both
like a wave and a particle.
However, he later emphasized that
electrons behave more like a wave.
Proposed that electrons be considered as
a wave confined in the space surrounding
an atomic nucleus.

19. Ernst Schrödinger 1887-1961
Quantum Mechanical Model
1926
Electrons are in probability zones
called “orbitals”, not orbits and
the location cannot be pinpointed
Electrons are particles and waves
at the same time
Developed quantum numbers
based on theories of Einstein and
Planck
Werner Heisenberg 1901-1976

20. Orbitals

21. Quantum Mechanical Theory
Electron in a Hydrogen atom

22. Quantum number describe the atomic
orbitals as well as the properties of the
electrons in those orbitals.
Quantum Numbers

23. Principal quantum number (n)-describes the
SIZEof the orbital or ENERGY LEVEL of the
atom.
Angular quantum number (l) or sublevels-
describes the SHAPEof the orbital.
Magnetic quantum number (m)-describes an
orbital's ORIENTATIONin space.
Spin quantum number (s)-describes the SPIN
or direction (clockwise or counter-clockwise) in
which an electron spins.
Quantum Numbers

24. Principle Quantum Number (n) or
Energy Level
integer values used to specify the shell/size/level
the electron is in
describes how far away from the nucleus the
electron shellor levelunder consideration is
the lower the number, the closer the energy level
is to the atom's nucleus and less energy
maximum # of electrons that can fit in an energy
level is given by formula 2n
2

27. Angular/Azimuthal Quantum
Number (l ) or Sub-level
determines the shapeof the orbital
they are numbered but are also given
letters referring to the orbital type
l=0 refers to the s-orbitals
l=1 refers to the p-orbitals
l=2 refers to the d-orbitals
l=3 refers to the f-orbitals

29. OrbitalLetter Designation
l Letter Maximum
Number of
Electrons
0 s 2
1 p 6
2 d 10
3 f 14

30. Magnetic quantum number (m
l)
or Orbitals
the third of a set of quantum numbers
tells us how many orbitals there are of a
particular type and their orientation in
space of a particular orbital
only two electrons can fit in an orbital
= electron

31. S –orbitals
only holds two electrons

32. P –orbitals
holds up to six electrons

33. http://www.ul.ie/~walshem/fyp/porbital.gif
P -orbitals

34. D –orbitals
holds up to 10 electrons

36. F –orbitals
holds up to 14 electrons

38. http://www.shsu.edu/~chm_tgc/BbAIF/PDB
s/applet/PDBorbitals.html

40. Spinquantum number (s)
the fourth of a set of quantum numbers
number specifying the direction of the spin
of an electron around its own axis.
only two electrons of opposite spin may
occupy an orbit
the only possible values of a spin quantum
number are +1/2 or -1/2.

42. Principle
Quantum # (n)
LEVEL/SIZE1 2 3 4
Angular
Quantum # (l)
ORBITAL
SHAPE or
SUBLEVEL
ss ps p ds p d f
Magnetic
Quantum #
(m)
AXIS/
ORIENTATION
orORBITALS
1
1
orbital
1 3
4 total
orbitals
1 3 5
9 total orbitals
1 3 5 7
16 total orbitals
Spin
Quantum # (s)
DIRECTION
OF
ELECTRON
SPIN
2 e-8 e- 18 e- 32 e-

43. Table 3-6b Orbitalsand Electron Capacity of the First Four Principle Energy
Levels
Principle
energy
level (n)
Type of
sublevel
Number of
orbitals
per type
Number of
orbitals
per
level(n
2
)
Maximum
number of
electrons
(2n
2
)
1 s 1 1 2
2
s 1
4 8
p 3
3
s 1
9 18p 3
d 5
4
s 1
16 32
p 3
d 5
f 7

45. Writing quantum mechanical
model of an atom
STEP 1: Give the ground state
electron configuration.
STEP 2: Give the orbital diagram.
STEP 3: Determine its quantum
numbers (n, l, m
l, m
s)

46. Quiz!!