Download Quantum Mechanics

Quantum Mechanics
In quantum mechanics, the electrons occupy
specific energy levels (as in Bohr's model) but
they also exist within specific probability
volumes
called
orbitals
with
specific
orientations in space. The electrons within
each orbital has a distinct spin.
n = The principle quantum number
Describes the possible energy levels and
pictorially it describes the orbital size.
n = 1, 2, 3…. where an orbital with the value of 2 is
larger than an orbital with the value of 1.
1s
2s
l
Quantum Mechanics
= angular momentum quantum number
Describes the "shape" of the orbital and can have values
from 0 to n - 1 for each n.
orbital designation :
s
p
d
f
Too hard to draw
see text
shape :
ml = magnetic quantum number
Related to the orientation of an orbital in space relative to
the other orbitals with the same l quantum numbers. It
can have values between l and - l .
ms = spin quantum number
An electron has either +1/2 or -1/2 spin values; sometimes
referred to as spin up and spin down.
ATOMIC
ORBITALS
Electron Configuration
Electron configuration is a shorthand
notation for describing the arrangement
of the electrons about the nucleus.
General Format using the quantum numbers:
n = principle quantum number
n l e- l = angular momentum quantum
number
e- = number of electrons
RULES:
1. Fill the lowest energy levels first.
Lowest
1s 2s 2p 3s 3p 4s 3d 4p
2. No more than two electrons per orbital.
Electron Configuration
Examples:
H : 1s1
He: 1s2
Li : 1s2 2s1
Co: 1s2 2s2 2p6 3s2 3p6 4s2 3d7
Br: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5
The condensed electron configuration distinguishes the
core electrons from the valence electrons. CORE
electrons are tightly held to the nucleus and resemble a
noble gas configuration. VALENCE electrons are the
outer most electrons and are involved in chemical
reactions.
Examples of the condensed configuration:
Li:[He] 2s1
Co:[Ar] 4s2 3d7
2
10
5
Orbital Shapes
Electron Configuration
Practice Problems
1. Give the full electron configuration:
C
O
Ne
Na
Si
Cl
Ar
K
2. Give the condensed electron configuration:
C O
Ne
Na
Si
Cl
Ar K
Answers on next slide
Electron Configuration
Answers
1 & 2. Give the full & condensed electron configuration:
C 1s2 2s2 2p2
or
[He] 2s2 2p2
O 1s2 2s2 2p4
or
[He] 2s2 2p2
Ne 1s2 2s2 2p6 or
[Ne]
Na 1s2 2s2 2p6 3s1
or [Ne] 3s1
Si 1s2 2s2 2p6 3s2 3p2 or [Ne] 3s2 3p2
Cl 1s2 2s2 2p6 3s2 3p5 or [Ne] 3s2 3p5
Ar 1s2 2s2 2p6 3s2 3p6 or [Ar]
K 1s2 2s2 2p6 3s2 3p6 4s1 or [Ar]4s1
Orbital Diagrams
Orbital diagrams are written in order of increasing energy
levels starting with the lowest energy level the 1s orbital.
___
___
___
___
___
___
___
___
___ ___ 4p
___ ___ ___ ___ 3d
4s
___ ___ 3p
3s
___ ___ 2p
2s
Remember the order!!
1s
RULES:
(1) fill the lowest
energy level first
(2) fill each orbital in
a subshell with one
electron first before
you double up.
(3) Completely fill
each subshell before
proceeding to the
next energy level.
Orbital Diagrams
Practice Problems
1. Fill in the orbital diagrams for:
C
O
Ne
Na
___ ___ ___ 4p
__ __ __ __ __ 3d
___ 4s
___ ___ ___ 3p
___ 3s
___ ___ ___ 2p
___ 2s
___ 1s
Si
Cl
Ar
K
___ ___ ___ 4p
__ __ __ __ __ 3d
___ 4s
___ ___ ___ 3p
___ 3s
___ ___ ___ 2p
___ 2s
___ 1s
Orbital Diagrams
Practice Problem Answers
Fill in the orbital diagrams for:
C
___ ___ ___ 4p
__ __ __ __ __ 3d
___ 4s
___ ___ ___ 3p
___ 3s
___ ___ ___ 2p
___ 2s
___ 1s
O
___ ___ ___ 4p
__ __ __ __ __ 3d
___ 4s
___ ___ ___ 3p
___ 3s
___ ___ ___ 2p
___ 2s
___ 1s
Orbital Diagrams
Practice Problem Answers
Fill in the orbital diagrams for:
Ne
Na
___ ___ ___ 4p
__ __ __ __ __ 3d
___ 4s
___ ___ ___ 3p
___ 3s
___ ___ ___ 2p
___ 2s
___ 1s
___ ___ ___ 4p
__ __ __ __ __ 3d
___ 4s
___ ___ ___ 3p
___ 3s
___ ___ ___ 2p
___ 2s
___ 1s
Orbital Diagrams
Practice Problem Answers
Fill in the orbital diagrams for:
Si
Cl
___ ___ ___ 4p
__ __ __ __ __ 3d
___ 4s
___ ___ ___ 3p
___ 3s
___ ___ ___ 2p
___ 2s
___ 1s
___ ___ ___ 4p
__ __ __ __ __ 3d
___ 4s
___ ___ ___ 3p
___ 3s
___ ___ ___ 2p
___ 2s
___ 1s
Group Study Problems
Orbital Diagrams
Fill in the orbital diagrams and then write the electron
configuration (both full and condensed) for:
B
F
Ca
P
___ ___ ___ 4p
__ __ __ __ __ 3d
___ 4s
___ ___ ___ 3p
___ 3s
___ ___ ___ 2p
___ 2s
___ 1s
S
As
Zn
Pb