Download 03 Atoms – Nuclides

02.2 Bohr‘s Atomic Theory
02.3 Notations
Nucleus:
Protons
Neutrons
Electron Orbits:
Electrons
Nucleon Number
Notation:
φ = 10-7 - 10-10 m
Neutron
(+)
(n)
Atomic Number
Nucleon Number
Proton
(-)
Nuclides
at present about 2500 types of different atoms – so called nuclides
– are known, they form 114 different chemical elements, only 274
nuclides are stable !
Chemical Elements
fundamental substance that cannot be further refined or subdivided
by chemical means. All atoms of a chemical element have the
same number of protons.
Proton Number
Element
1
1
1
H
1
4
2
4
He
2
12
6
12
C
6
03.1 Chart of Nuclides
03 Atoms – Nuclides - Elements
Atoms
particles that form matter
Element
Isotopic Nuclides
Atoms which have the same atomic number but different mass
numbers
He
He-3
He-4
He-5
He-6
4,002602
0,000137
99,99986
99,99986
806,7 ms
3β−
n
σabs < 0,05
σ 0,00005
0,02
H
H-1
H-2
H-3
1,00794
99,985
0,015
12,323 a
σ 0,332
σ 0,332
σ 0,00052
β- 3,5
Z
β− 0,02
n1
10,25 m
β− 0,8
N
1
03.2 Nuclid Categories
03.3 Chart of Nuclides - FZ Karlsruhe
Isotopic nuclides
Atoms which have the same atomic number but different mass
numbers
Isobaric nuclides
Atoms which have the same mass number but different proton
numbers
Isotonic nuclides
Atoms which have the same neutron number but different
proton numbers
Isomeric nuclides
Atoms which have the same proton and neutron numbers but
different energy levels
03.4 Chart of the Nuclides
03.5 Chart of the Nuclides TOICD (1)
legend
Karlsruhe Chart of Nuclides: all known nuclides
X axis: number of protons
Y axis: number of neutrons
Colours and symbols:
stable nuclides
positron decay
β+
electron capture
ε
negatron decay
β-
alpha decay
α
spontaneous fission
sf
proton decay
p
isomer decay
Iγ
2
03.7 Hydrogen Isotopes
03.6 Chart of the Nuclides TOICD (2)
1
1
Hydrogen
2
1
3
1
04 The Standard Model
04.1 Elementary Particles & Quarks
Elementary Particles
Matter Atom Nucleus Electron Proton Neutron Quark
Leptons
light particles
Mesons
even quark numbers
Neutrinos
...
Elektrons
...
Baryons
heavy particles
Hyperons
...
Bosons
"force particles"
Nucleons
Neutrons
Protons
Quarks
Quarks
Photons
...
3
04.2 Leptons - light particles
name
symbol
Electron
Müon
Tau
eµτ-
e+
µ+
τ+
rest
mass
[MeV]
charge
0,511
105,6
1784
-1 +1
-1 +1
-1 +1
spin
mean
lifetime
[s]
1/2
1/2
1/2
stable
2. 10-6
3. 10-13
04.3 Mesons name
symbol
Pionen
135
Kaonen
π0
π+ π−
K0K0
Pionen
rest
mass
[MeV]
2 quark particles
charge
0
140
+1 -1
498
0 0
494
+1 -1
quark
sequences
spin mean
lifetime
[s]
uu
dd
0
8.10-17
ud
du
0
2,6 .10-8
ds d s
0
10-10 -5.10-8
us
0
1,2.10-8
Electron- Neutrino νeνe
?
0
0
1/2
stable ?
Kaonen
K+
Müon-Neutrino
νµνµ
?
0
0
1/2
stable ?
J / Psi
J/Ψ
3098
0
cc
1
1.10-20
Tau-Neutrino
ντ ντ
?
0
0
1/2
stable ?
D-Null
D0
1863
0
cu
0
1.10-12
D-Plus
D+
1863
1
cd
0
4.10-13
Ypsilon
Y
9460
0
bb
1
1.10-20
leptons + quarks
= fundamental structures of matter
04.4 Baryons name
symbol rest
mass
[MeV]
Proton
p p
938,3
Neutron
n n
939,6
Lambda
Λ Λ
1115
Sigma-Plus
Σ+ Σ+
1189
Sigma-Minus
Σ− Σ−
1197
Sigma-Null
Σ0 Σ0
1192
Xi-Minus
Ξ− Ξ−
1321
Xi-Null
Ξ0 Ξ0
1315
Omega-Minus Ω−Ω−
1672
Charm-Lambda Λc Λc
2280
heavy particles
charge
+1
0
0
+1
-1
0
-1
0
-1
+1
-1
0
0
+1
-1
0
1
0
-1
+1
quark
sequences
u u d uud
d d u ddu
u d s uds
u u s uus
d d s dds
u d s uds
d s s dss
u s s uss
s s s sss
u d c udc
spin mean
lifetime
[s]
½
stable
½
ca. 900
½
2,6.10-10
½
8.10-11
½
1,5.10-10
½
6.10-20
½
1,6.10-10
½
3.10-10
½
8.10-11
½
2.10-13
K−
04.5 Eichbosons -
name
symbol
rest
mass
[MeV]
su
exchange particles
charge
spin
mean
lifetime
[s]
Photon
W-Teilchen
Z-Teilchen
Gluon
γ
W + W−
Z
g
?
~83 000
~93 000
0
0
1
0
0
1
-1
1
1
stable
10-25
10-25
stable
exchange particles: force transmitters
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04.6 Quarks -
04.7 „Visual“- Quarks
particle „substructures“
name
symbol
rest
mass
[MeV]
charge
up
down
strange
charm
bottom (beauty)
top (truth)
u u
d d
s s
c c
b b
t t
~5
~10
~100
~1500
~4700
?
2/3
-1/3
-1/3
2/3
-2/3
1/3
1/3
-2/3
-1/3
1/3
2/3 -2/3
spin mean
lifetime
[s]
½
½
½
½
½
½
top
up
stable
variable
variable
variable
variable
variable
down
bottom
strange
charm
3 quark elementary particles : baryons
2 quark elementary particles : mesones
05 Antimatter
• All elementary particles have antimatter counter parts, antimatter
counterparts have the same mass but opposite electric charges
• When matter and antimatter come in contact they are instantly
converted to energy (annihilation) and photons or mesons were
created, respectively
• Photons are identical with its antimatter.
06 Stable and Instable Nuclides
nucleon
mass
[g]
relative
charge spin
t1/2
atomic mass
beta decay
[u]
Proton
1,672 x 10-24
1,00728
+e
Neutron 1,674 x 10-24
1,00867
0
1
1
2
h
stable
2
h
12 min
1 u = 1,660 x 10-24 g = 931,5 MeV
5
06.1 Mass Defect
Mass defect is the mass difference between the nuclide rest mass
and the free nukleon rest masses.
06.2 Nucleus Binding Energy
Mean Binding Energy per Nucleon
Mass defect is proportional to the nucleon bonding energy.
alpha particle mass defect:
∆m = malpha
∆m = 4,00151
≅ 28 MeV
- (2 x mproton - 2x mneutron)
- (2 x 1,00782 + 2 x 1,00866) = 0,0307u
Mass Number
06.3 Radioactivity
•
•
•
•
06.4 Activity
Radioactivity is the ability of an unstable atomic nucleus to transform into a
stable product or another unstable product while emitting radiation. This
transformation and emission of energy is called radioactive decay. A
transformation from one element to another is known as a transmutation. The
radiation can be emitted in several forms, including:
The becquerel (symbol Bq) is the SI derived unit of radioactivity,
defined as the activity of a quantity of radioactive material in which
one nucleus decays per second. It is therefore equivalent to s-1. The
older unit of radioactivity was the curie (Ci).
a positively charged alpha particle (α), which is the same as a helium nuclei
consisting of two neutrons and two protons
a negatively charged beta minus particle (β-), which is the same as an electron
a positively charged beta plus particle (β+), which is the same as a positron, a
particle of equal mass but opposite charge of an electron
a gamma ray (γ), which is a photon, a particle with a exceedingly high wave
frequency and energy (visible light and radio waves are also photons, as well as
all other electromagnetic radiation).
An additional radioactive process is nuclear fission, where some elements can
split as a result of absorbing an additional neutron
1 Gramm Radium-226: 37 .109 disintegrations per second
37 .109 Bq = 1 Curie (Ci)
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06.5 The Radioactive Decay
A
exponential decay
A
t½
t
06.6 The Decay Law
Activity
half life
time
A(t )= A0 ⋅ e
t½
t
The half-life of a radioactive isotope is the time it takes for half of
the atoms in a pure sample of the isotope to decay into another
element. It is a measure of the stability of an isotope; the shorter
the half life, the less stable the atom. The decay of an atom is said
to be spontaneous as one can only determine the probability of
decay and not predict when an individual atom will decay
06.7 Decay Examples
Radionuclide Occurancy Decay Type
Tritium
Ra - 226
I - 131
Cs - 134
U - 235
U - 238
0,00013 %
β
α/γ
β- / γ
β/γ
0,720 % α, β−, γ, sf *
99,28 %
α, β−, sf
* sf means spontaneous fission
12,346
1,6 . 103
8,04
2,06
2,09
7,030 . 108
4,468 . 109
ln 2
⋅t
t1 / 2
= Activity after t
= time
= Activity at t = t0
= half life
06.8 The Natural Acivity of a
Standard Person
(20 -
Half Life t1/2
-
A(t)
t
A0
t½
−
a
a
d
a
h
a
a
Radionuclide
Activity in Bq
K - 40
4 500
C -14
3 800
Rb - 87
650
Pb - 210, Bi - 210, Po - 210
60
Daughters Rn - 220
30
H-3
25
Be - 7
25
Daughters Rn - 222
15
Others
7
Sum
9 112 (ca. 230 Bq / kg)
30 y,
7
0 kg)
7
06.9 Spezific Activity in Food
Food
KCl salt
Vegetarian food
Reindeer liver (Po-210)
Brazil nut (Ra- 226)
Activity in Bq / kg
15 944
40*
222
132
Food
120 g bread
25 g camenbert
25 g corned beef
20 g Nutella
125 ml black tea (Turky)
Activity in Bq
2,0
0,9
1,2
3,2
6,5
Nicht
verkehrsfähig !
100 g cottage cheese
25 g blue berries
* average
06.11 Activity of a Lunch
Food
Activity in Bq
150 g wild animal meat (Niedersachsen)
87,2
60 g pasta
0,6
200 g Marones (Niedersachsen)
210,6
Not
permitted !
20 g canned peach
10 g red berries (Skandinavia)
150 g vanilla ice cream
50 g cherries
06.10 Activity of a Breakfast
1,0
0,0
3,0
16,7
0,2
2,4
07.4 Shell Model of the Nucleus
• Strong Interaction Models
– strong nucleon interactions
– strong perturbations with movements
• Independant Particle Models
– weak nucleon interactions
– no perturbations, independent movements
– shell model: analog electron shells
– 2(2l+1) nucleons per shell
– bonding energy approximatively independent from shell
number
– no force center but potential minimum
– strong interactions between spin and orbital rotations
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07.6 The 4 Fundamental Forces
08 Nuclear Physics
Nuclear Fission
• electromagnetic force
uranium + 1 neutron Ö disintegration
• gravitational force
• strong nucleus interactions
(ca. 2,0 x 10-13 cm reach)
nucleon bonding
• weak nucleus interactions
(ca. 0,5 x 10-13 cm reach)
quark bonding
causes radioactiv decay !
08.1 Nuclear Chain Reaction
08.2 Fission Product Yields
Fission Yield
U-235
Nuclear Fission
U-235 + 1n
Ø
Fission Products + 2.3 n
Mass Number
9
09.1 Artificial Nuclear Reactions
09 Nuclear Reactions
α,N reactions
e-, He++ capture
0
−1
e +
→
40
19
K
40
18
Ar
n capture
1
0
n +
B →
10
5
Li +
7
3
4
2
13N
13C
14N
+ 1H
+ 1H
15O
15N
+ 1H
→
→
→
→
→
→
13N
+γ
13C + e+ + ν
e
14N + γ
15O + γ
15N + e+ + ν
e
12C + 4He
+ 1,95 MeV
+ 1,37 MeV
+ 7,54 MeV
+ 7,35 MeV
+ 1,86 MeV
+ 4,96 MeV
14
7
N
→
18
93
F
→
O +
17
8
1
1
p
He + γ
Bethe-Weizsäcker Cycle
+ 1H
He +
4
2
09.2 The CNO (carbon-nitrogenoxygen) Cycle
12C
14N(α,p)17O
Lebensdauer
1,3·107 Jahre
7
Minuten
2,7·106 Jahre
3,2·108 Jahre
82
Sekunden
1,12·105 Jahre
09.3 The Proton Proton (PP) Reaction
1H + 1H
e+ + e2H + 1H
3He +3He
3He
+
+ e7Li + 1H
7Be
3He
7Be
While the proton-proton chain is more important in stars the size of the sun or
less, theoretical models show that the CNO cycle is the dominant source of
energy in heavier stars. The cycle results in the fusion of four hydrogen nuclei
(1H, protons) into a single helium nucleus (4He, alpha particle), which supplies
energy to the star in accordance with Einstein's equation. Ordinary carbon
serves as a catalyst in this set of reactions and is regenerated (3,4·108 y)
4He
8B
8Be
4He
+
+ 1H
→
→
→
→
2H
+ e+ + νe
2γ
3He + γ
4He + 1H + 1H
→
→
→
7Be
→
→
→
↔
7Be
+γ
+ νe
4He + 4He
+ 0,42 MeV
+ 1,02 MeV
+ 5,49 MeV
+ 12,86 MeV
10–14 106 Kelvin
7Li
+γ
+γ
8Be + e+ + ν
e
4He + 4He
14–23 106 Kelvin
8B
>23 106 Kelvin
The proton-proton chain reaction is one of two fusion reactions by which stars convert
hydrogen to helium, the other being the CNO cycle. The proton-proton chain is more
important in stars the size of the Sun or less
10
Atomic Physicists
Hans Bethe
Niels bohr
John Chadwick
Marie Curie
Pierre Curie
Paul Dirac
Albert Einstein
Otto Hahn
Liese Meitner
Max Planck
Robert Oppenheimer
Ernest Rutherford
Snyder
Arnold Sommerfeld
Fritz Straßner
Carl Friedrich von Weizäcker
Exercises (1)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Exercises (2)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
What are nucleons ? Which nucleons you know ?
Wxplain the quark structure of protons ?
Which elementary particles type are electrons, protons, neutrons ?
What is the design of the antiproton ?
What is the design of the antiphoton ?
What are quarks ?
Explain the mass defect !
Which are the 4 fundamental forces ?
What is nuclear fusion ? Which nuclides are favorised ?
What is nuclear fission ? Which nuclides are favorised ?
What are the conclusions from the RUTHERFORD experiment ?
What is the definition of the atomic number ?
What is the definition of the mass number ?
Which are the three hydrogen isotopes ?
Do the hydrogen isotopes show different physical properties ? Why ?
Do the hydrogen isotopes show different chemical properties ? Why ?
What are isomeric nuclides ?
How many electrons can be filled in the L-shell ?
What is a stationary wave ?
What is an electron orbital ?
References
1.
2.
3.
4.
5.
B. Bröcker; DTV-Atlas zur Atomphysik; DTV-Verlag, 1993
R.B. Firestone; CD: Table of Isotopes; Wiley-Interscience, 1996
S. Hawking; CD: Eine kurze Geschichte der Zeit; Navigo, 1997 B. Bröcker;
DTV-Atlas zur Atomphysik; DTV Verlag 1993
P.M. Magazin 12 / 94
Bild der Wissenschaft 11 / 1996
11
Web-Links
http://atlasinfo.cern.ch/Atlas/documentation/EDUC/physics1.html
http://users.senet.com.au/~rowanb/chem/atstruct.html
http://newton.ex.ac.uk/aip/physnews.412.html#1
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