Lecture 1 Summary.
Bohr Model of H atom .
↳
treats H atom as neutron and e (as particles)
Postulates :
c'moves circular orbits around nucleus
·
in +ve
circular orbit is Stable (this physics)
·
is a breach of classical
·
out
moving between
orbits
gives energy.
between
e-
·
c has mass m and velocity v
Scentripetal Feedrostatio
·
..
due to
the nucleus and-ree
multiple
Bohrassumed
the
angular momentum of e can only be integer
Con'h
This allowed
eq for .
r to be derived : r
=me'
ran
in :
10 "om o
When n = 1
,
r = 0 52917 A
.
(Bohr's radius)
This seems credible as viscosity measurements of H indicate diameter : In
,
gas
Energy of 11 atom
from sum of PE and KE .
PE is work
required to remove c from nucleus - S
Total
energy ,
I =
-(we Ex-
Wave-particle duality
de
Broglie stated all matter has both wave and particle characteristics.
, Atomic structure
Darisson and Germer used e and Ni film
gun
an
reflection (particle property
--
diffraction (wave properly
--
Photoelectric effect uses metal film with low work
function (easilyionised) g K Na Rb and
.
e .
,
,
light of high energy (above
monochromatic work
function threshold)
shighouse
Particles have mass and velocity Waves have Xt
.
Wave properties only apply toliny objects
-
wavelength
e C
g
.
.
KE of a wave is
given by
how curved it is
(a)
, Atomic structure
Lecture 2 Summary .
e as a wave in 1D.
(particle in a box")
-
vePE -
vePE
"I E
&
1- e - >
e is repelled by walls (both-ve)
x = 0 x= L
Shrodinger eq .
used to describe behaviour of wave in an
energy/force field
ID 1 quantum number
(Sin()
=
↑n(x) = n = 1 2 3 ...
Y wavefunction wave heiht
,
,
= =
g at
point o
n = 1 po in =
n =
2 Po Y =+ ve
X
x=
i L
E 2 = =
4
Y = -
ve
E 32 9
i i
= =
n = 3 4
, X
o
* node =
x= L
N +ve >
-
-ve
Energy of wave
,
E : Ean2
Energy of the e is never O as it always has KE from repulsion due to -ve walls