2286383
Descripción
Mapa Mental por ainearrigan, actualizado hace más de 1 año
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Creado por ainearrigan
hace más de 9 años
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The atom, the Nucleus
and Radioactivity
- The atom
- The plum pudding model
- Rutherfords expt.
- he believed
the model and
expected the
alpha particles
to go through
the gold foil
- results - atoms are composed mainly of empty space
have an extremely positive centre
- thought that there was an electron
cloud surrounding the nucleus
- thought that there was an electron
cloud surrounding the nucleus
- he believed
the model and
expected the
alpha particles
to go through
the gold foil
- the arrangement of electrons
- Neils Bohr - believed electrons existed
in 'energy levels' this was proofed by
the emission spectrum
- types of spectra
- Continuous produced by a
liquid or solid a continuous
spectrum is emitted unable to
detect the element stic
- a line spectrum is produced by gaseous
matter, it is charateristic
- Continuous produced by a
liquid or solid a continuous
spectrum is emitted unable to
detect the element stic
- Emission spectrum
- every element gives out its own unique emission spectrum
- LASERS- Light amplification by stimulated emission of radiation
- Produce an intense beam of light, the
electrons recive energy and go to the same
energy level and then emit the same
wavelength photon
- used to treat eye problems
- used for telecommunication in optical fibers
- used in welding and cutting
- used in target designation
- used to treat eye problems
- Produce an intense beam of light, the
electrons recive energy and go to the same
energy level and then emit the same
wavelength photon
- LASERS- Light amplification by stimulated emission of radiation
- E2-E1=hxf
- E2-E1 (difference in energy
levels) h= planks constant
f=frequency
- E2-E1 (difference in energy
levels) h= planks constant
f=frequency
- c= f x ^
- every element gives out its own unique emission spectrum
- Bohrs theory
- types of spectra
- Neils Bohr - believed electrons existed
in 'energy levels' this was proofed by
the emission spectrum
- Rutherfords expt.
- The plum pudding model
- Radioactivity
- Henri Becquerel
discovered that a
crystal of uranium was
emitting some kind of
light. Marie Curie later
went on to research
more and name this
occurance as radiation.
- natural radiation - the spontaneous
decay of a nucleus, with the
emission of some form of radiation
- artificial radioactivity- radioactivity from atoms
caused b nuclear bombardment
- The activity of the radioactive nucleus
- the number of nuclei of a radioactive sample decaying per
second= activity (A) / Becquerel (Bq)
- the number of nuclei of a radioactive sample decaying per
second= activity (A) / Becquerel (Bq)
- The law of radioactive decay
- no. of nuclei decaying at that
moment is proportional to the
no. undecayed @ that instant
- RATE OF DECAY= ^ x N
- N- the no. of undecayed atoms
^ - decay constant
- each isotope has its own decay constant
- the rate decreases as time goes on
- Half- life (T 1/2) - the time taken for half of the undecayed atoms in an sample of the element to decay
- N- the no. of undecayed atoms
^ - decay constant
- RATE OF DECAY= ^ x N
- no. of nuclei decaying at that
moment is proportional to the
no. undecayed @ that instant
- Henri Becquerel
discovered that a
crystal of uranium was
emitting some kind of
light. Marie Curie later
went on to research
more and name this
occurance as radiation.
- Detecting nuclear radiation and uses
- Geiger-Muller tube or solid state detector
- - radiation passes through the
window of the tube and ionises
the gas - the e- are accelerated
towards the anode causing
more ionization -this induces a
small current which measures
the pulse time for each ionizing
particle -it cant tell the type of
radiation
- - radiation passes through the
window of the tube and ionises
the gas - the e- are accelerated
towards the anode causing
more ionization -this induces a
small current which measures
the pulse time for each ionizing
particle -it cant tell the type of
radiation
- medical - cancer treatment
- carbon dating (c-14)
- used in fertilisers
- preservation of spices in food
- Geiger-Muller tube or solid state detector
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