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Video on scale of universe Excellent Flash on biological cells Excellent Flash on scale of universe
Atomic Structure
Atomic Size radius Order of magnitude – (10-10– 10-12)m
Radius Li atom – (1.5 x 10-10)m Radius nucleus – (1 x 10-14)m
Scale of matter from smallest to largest
1nm – 1 x 10-9 m 1pm – 1 x 10-12 m 1A - 1 x 10-10 m
Radius Li
atom
Radius Nucleus
Li atom Elementary particles making up nucleon (protons + neutrons)
Nucleon - (proton + neutron) Proton – 2 up quark + 1 down quark Neutron – 2 down quark + 1 up quark
Unit conversion
Video on new particles physics
Atomic Structure
1nm – 1 x 10-9 m 1pm – 1 x 10-12 m 1A - 1 x 10-10 m
Radius Li
atom
Radius Nucleus
Li atom Elementary particles making up nucleon (protons + neutrons)
Unit conversion
Structure within atom Discovery particles with help of Large Hadron Collider
Nucleon - (proton + neutron) Proton – 2 up quark + 1 down quark Neutron – 2 down quark + 1 up quark
Atomic Size radius Order of magnitude – (10-10– 10-12)m
Radius Li atom – (1.5 x 10-10)m Radius nucleus – (1 x 10-14)m
Video on new particles physics
Higgs Boson Discovery Wins Nobel Prize for Physics
Video on Higgs field part 2
Video on Higgs field part 1
Video on timeline discovery Structure within atom
Recent discovery particles from Large Hadron Collider
Higgs boson leftover excitation of particles of Higgs field
Discovery of Higgs boson and Higgs field
Particles interact with Higgs field to produce mass
Video on NOBEL PRIZE 2013 !!!!!!
Discovery timeline to Quantum model Discovery of elementary particles Elementary particles
Video (Minute physics) Video (Ted Talk) Video (RI) Video (Veratasium)
Video on Higgs field
Elementary particles Structure within atom Recent discovery particles from
Large Hadron Collider
Higgs boson leftover excitation of particles of Higgs field
Discovery of Higgs boson and Higgs field
Particles interact with Higgs field to produce mass
Mass (proton + neutron)- due to interaction bet up quarks/down quarks with gluons (energy fluatution)
Proton -2 up quarks
1 down quark
Neutron -1 up quark
2 down quarks
What is Higgs Boson ? What is Higgs Field ?
Excellent videos –Particles interact with Higgs field create MASS
Nuclear reaction vs Chemical rxn
Nuclear rxn Involve proton/neutron in nucleus
Decomposition of nucleus into smaller nuclei Energy released greater
Conservation of charge/atomic mass number
Chemical rxn Involve outer most elec
Transfer/sharing/loss of elec Energy released less
Conservation of mass and charge
2Na + CI2 2NaCI
Type radiation
Nature radiation
Symbol Penetration (mass,m/charge,e)
Ionising power (removing electron)
Alpha Helium nucleus
α Low ratio (high m/e)
High
Beta High energy electron
β Moderate Moderate
Gamma High frequency electromagnetic
radiation
γ High ratio (small m/e)
Low
Type of radiation
Nuclear equation- decay of nucleus Chemical equation – valence electron
Transfer electrons
Sharing electrons
Nuclear rxn
Alpha Decay Losing an alpha particle – helium nucleus Daughter nuclei lower in proton number
Mass of 4 (2 proton + 2 neutron) +2 charged (only 2 protons) = +2
Decay of uranium, thorium, actinium
Beta Decay Losing beta particle –Electron/positron
Daughter nuclei higher in proton number Negative charge (-1)
Decay neutron proton + electron
Alpha Decay Beta Decay
Gamma Decay
Gamma decay Losing γ particle - EM radiation high frequency
Daughter nuclei no change in atomic mass
α β
Unstable nucleus atom Decay by emitting ionizing particles
+
Video on γ decay Video on β decay Video on α decay
Alpha, Beta, Gamma Radiation
Alpha Decay Lose alpha particle – helium nucleus
Mass He- 4 (2 proton + 2 neutron) +2 charged (2 proton + 2 neutron + 0 e)
Daughter nuclei lower in proton number
Beta Decay Lose beta particle –Electron/beta β
Negative charge (-1) -1 charged (β / electron)
Daughter nuclei higher in proton number
Gamma decay Lose γ particle –EM radiation of high frequency
Daughter nuclei no change in atomic mass
Nucleus > 84 proton Unstable, radioactive decay
Decay depend ratio neutron/proton
Decay depend ratio neutron/proton Neutron/proton ratio LOW – Proton rich
Decay to reduce proton Alpha decay, α (proton number )
Mass number alway Conserved
Decay depend ratio neutron/proton Neutron/proton ratio HIGH – Neutron rich
Decay to reduce neutron Beta decay β ( Neutron Proton + electron)
Ratio decrease
Decay depend ratio neutron/proton Neutron/proton ratio HIGH /LOW
Gamma decay γ, is associated along with Alpha and Beta
Radioactive isotopes Half-life
Uranium 238 4.5 x 109
Carbon-14 5.7 x 103
Radium-226 1.6 x 103
Strontium-90 28 years
Iodine-131 8.1 days
Bismuth-214 19.7 minutes
Polonium-214 1.5 x 10-4
Isotopes
Stable Isotopes Unstable Isotopes
Unstable Isotopes – emit radiation
RADIOISOTOPES
Simulation isotope 12C, 13C, 14C
Radioisotopes Half-life – time taken for conc/amt/number/activity isotope to fall to half of its original value. Half life decay – always constant
Shorter half-life More unstable, decay fast
Long half-life More stable, decay slowly
Emit radiation form unstable isotope
Simulation isotope 1H, 2H, 3H
Video on Half life
Simulation half life C-14/uranuim
Half-life
Conc/amt/number/activity
Carbon – 3 Isotopes
Radiocarbon/carbon dating
Half life C-14 = 5730 yr Beta (β/electron ) decay
Conclusion Ratio C14/C12 constant is organism alive
Ratio C14/C12 drop organism die
Uses Age dead organic fossil contain Carbon
Max age limit 60,000 yrs old.
Abundance – 99% (Stable) Abundance – 1% (Stable) Abundance – trace amt (Unstable , radioactive)
How is form? • C-14 produce in stratosphere when neutron hit nitrogen atom to form C-14 •C-14 to N-14 by converting neutron proton (proton stay in nucleus), electron emit as β radiation • emit as β ray.
(proton in nucleus – increase proton number)
emit as β ray. •Ratio C14/C12- constant if alive – TAKE in C14 (C12 constant) •Ratio C14/C12- drop if dead - NOT taking C14. (C12 constant)
How it is form?
Carbon -12 Carbon -13 Carbon -14
Click to view simulation
Radiocarbon/carbon dating
Half life C-14 = 5730 yr Beta (β/electron ) decay
Carbon -14
Abundance – trace amt (Unstable , radioactive)
How is form? • C-14 produce in stratosphere when neutron hit nitrogen atom to form C-14 •C-14 to N-14 by converting neutron proton (proton stay in nucleus), electron emit as β radiation • emit as β ray.
(proton in nucleus – increase proton number)
emit as β ray. •Ratio C14/C12- constant if alive – TAKE in C14 (C12 constant) •Ratio C14/C12- drop if dead - NOT taking C14. (C12 constant)
Video C-14 Carbon Dating Video C-14 Carbon Dating Video C-14 Half life Carbon Dating
Simulation C-14 (Half life) At 100% (Starting)
Simulation C-14 (Half life) At 50% (Starting)
Video Radiocarbon dating
How Radiocarbon dating work?
Video on Radio tracer
Radiocarbon/carbon dating
Half life C-14 = 5730 yr
Carbon -14
Beta (β/electron) decay
Video on C-14 Carbon Dating
Video Radiocarbon dating
How Radiocarbon dating work?
Uses of radioactive isotopes
Radiotherapy/cancer/tumour Tracers/studying metabolic pathways
Cobalt-60
Half life Co-60 = 5.27 yr Half life I-131 = 8 days
How Gamma rays works? How Radio tracer works?
Iodine-131
Sterilization – killing bacteria/germ Radiotherapy – kill tumor cells
High energy electromagnetic ray
Gamma γ + β decay
Carbon dating Age of fossil remains
Radio tracer Trace pathway in body
Beta β (90%) and γ (10%) decay
Gamma γ + β decay
Radioactive decay Half life formula
tA
A
o
t ][
][ln
t
t
t
o
t
eAA
eA
A
0][][
][
][
2ln2/1 t
2/15.0t
t
oAA
][. AdecayRate
First order
n
oAA 5.0
Final conc
Decay constant
Half life
Initial conc
Time
Half-life – time taken for conc/amt/number/activity isotope to fall to half of its original value. Half life decay – always constant
Bismuth-212 half life 1 hr. How long take for 16 g sample to decay, so 1g remain
Time/h Mass left/g
0 16
1 8
2 4
3 2
4 1
Time = 4h
method 1 method 2
hrtime
e
eA
A
t
t
o
t
4
16
1
][
][
693.0
693.01
693.0
2ln
2/1
t
Initial conc isotope sample is 1.4 10-6 M . Find half life, if conc left is 1.365 x 10-6M after 2 hr
1
6
6
0126.0
2]104.1[
]10365.1[ln
][
][ln
hr
tA
A
o
t
hrt
t
550126.0
2ln
2ln
2/1
2/1
Number Half life
Explain why it is impossible to state how long an individual uranium to decay
Time for individual atom to decay is not fixed. Half life is average time for many diff atoms
Radioactive decay Half life formula
tA
A
o
t ][
][ln
t
t
t
o
t
eAA
eA
A
0][][
][
][
2ln2/1 t
2/15.0t
t
oAA
][. AdecayRate
First order
n
oAA 5.0
Final conc
Decay constant
Half life
Initial conc
Time
Number Half life
Rn half life 1620 yrs. Find decay constant Deduce proportion of sample remain after 100yr
%8.95958.0][
][
][
][
][
][
100000428.0
o
t
o
t
t
o
t
A
A
eA
A
eA
A
1
2/1
000428.01620
693.0
2ln
yr
t
2ln2/1 t
Rn half life 1622 yrs. Find how long it will take a sample to decay to 10% of its original sample
2ln2/1 t
1
2/1
000427.01622
693.0
2ln
yr
t
yrstime
e
eA
A
t
o
t
t
o
t
5392
%]100[
%]10[
][
][
000427.0
An isotope has half life of 69 yr. Find how long it take for activity in waste to decrease by 99%
2ln2/1 t
1
2/1
01.069
693.0
2ln
yr
t
yrstime
e
eA
A
t
o
t
t
o
t
461
]100[
]1[
][
][
01.0
[A]t = (100 – 99) = 1%
Potassium-argon rock dating. Potassium decay to argon, argon is trap in rock.
A sample contain 7 x 1010 potassium, 3 x 1010 argon. Cal original potassium present and age of rock. Half life
potassium = 1.26 x 109
Initial potassium = (7 x1010 + 3 x 1010) = 10 x 1010
19
9
2/1
1055.01026.1
693.0
2ln
yr
t
yrtime
t
tA
A
o
t
o
t
8
9
10
10
1047.6
1055.0]1010[
]107[ln
][
][ln
tA
A
o
t ][
][ln
t
t
t
o
t
eAA
eA
A
0][][
][
][
2ln2/1 t
2/15.0t
t
oAA
][. AdecayRate
First order
n
oAA 5.0
Final conc
Decay constant
Half life
Initial conc
Time
Piece wood found to have activity of 10 cpm g-1 of carbon . New wood has count of 15 cpm g-1. Half life C-14 is 5570 yr. Find
age of wood.
yrstime
e
eA
A
t
o
t
t
o
t
3270
]15[
]10[
][
][
000124.0
1
2/1
000124.05570
693.0
2ln
yr
t
2ln2/1 t
Mass sample was measured, and re-measured 120 days later. 56% of original sample remain. Find half life
2ln2/1 t
dayst
t
14300483.0
693.0
2ln
2/1
2/1
100483.0
120%]100[
%]56[ln
][
][ln
day
tA
A
o
t
o
t
Sample half life 0f 8hr has activity of 450 unit after 48hr. Find original activity
2/15.0t
t
oAA n
oAA 5.0Number Half life n = 48/8 = 6
unitA
A
AA
o
o
t
t
o
28846
5.0450
5.0
8
48
2/1
unitA
A
AA
o
o
n
o
28846
5.0450
5.0
6
Sr -90 half life of 28 yr. Find how much sample left after 280 yr
2/15.0t
t
oAA n
oAA 5.0Number Half life n = 280/28 = 10
%098.0
5.0
5.0
28
280
2/1
o
o
t
t
o
A
A
AA
AA
%098.0
5.0
5.0
10
o
o
n
o
A
A
AA
AA
Radioactive decay Half life formula
Number Half life
yrstime
t
tA
A
o
t
22460
000121.060
4ln
][
][ln
% material decay 100% – 0.1% = 99.9% decay
Radioactive decay Half life formula
tA
A
o
t ][
][ln
t
t
t
o
t
eAA
eA
A
0][][
][
][
2ln2/1 t
2/15.0t
t
oAA
][. AdecayRate
First order
n
oAA 5.0
Final conc
Decay constant
Half life
Initial conc
Time
Piece wood found to have activity of 6 cpm g-1 of carbon . New wood has count of 15 cpm g-1. Half life C-14 is 5280 yr.
Find age of wood.
yrstime
e
eA
A
t
o
t
t
o
t
6980
]15[
]6[
][
][
000131.0
1
2/1
000131.05280
693.0
2ln
yr
t
2ln2/1 t
Fission product from nuclear shd be isolated for 10 half life. Find fraction radioactive remain after this time.
Deduce % material decay in this time
C-14 in atmosphere produce 60 count hr-1g-1. Sample sea shell found to have 4 count hr-1 g-1. estimate age of shell. Half life C-14 is 5730yr
Pu half life 88yr. Explain why activity sample is constant over 1 yr. Find % sample remain after 20 yrs.
n
oAA 5.0Number Half life n = 10
%1.0
5.0
5.0
10
o
o
n
o
A
A
AA
AA
remain
2ln2/1 t
1
2/1
000121.05730
693.0
2ln
yr
t
1 yr short compare to half-life, 88 yr, Pu activity doesnt change much
2ln2/1 t
1
2/1
007877.088
693.0
2ln
yr
t
854.0][
][
][
][
][
][
20007877.0
o
t
o
t
t
o
t
A
A
eA
A
eA
A
= 85.4 %
Number Half life
