Particles Flashcards
what are the 3 constituents that makes up an atom
protons neutron and electrons
what is found at the center of an atom and what is it made up of
a nucleus and is made up of protons and neutrons
what are protons and neutrons also known as
nucleons
where are electrons found in an atom
they are found in shells orbiting the nucleus
what is the charge of a proton neutron and electron
proton - +1.6x10^-19
electron - -1.6x10^-19
neutron - 0
what is the relative charge of a proton neutron and electron
proton - +1
electron - -1
neutron - 0
what is the mass of a proton neutron and electron
proton and neutron - 1.67x10^-27
electron - 9.11x10^-31
what is the relative mass of a proton neutron and electron
proton and neutron - 1
electron - 0.0005
what is the specific charge of a proton neutron and electron
proton - 9.58x10^7
neutron - 0
electron - 1.76x10^11
what are the units for specific charge
CKg^-1
what is the specific charge of a particle and how do you calculate it
the charge-mass ratio and is calculated by dividing a particles charge by its mass
what is an isotope
are atoms with the same number of protons but different numbers of neutrons
what is an example of an isotope
carbon-14 is a radioactive isotope of carbon which can be used to find the approximate age of an object containing organic material. this is done through carbon dating, which involves calculating the percentage of carbon-14 remaining in the object, and using the known starting value of carbon-14 and its half life to calculate an approximate age
how does the strong nuclear force keep the nuclei stable
by counteracting the electrostatic force of repulsion between protons in the nucleus(as they have the same charge). it only acts on nucleons and has a very short range, where it is attractive up to separations of 3 fm, but repulsion below separations of 0.5 fm,
what causes an unstable nuclei
when an atom has too many of either protons, neutrons or both causing the SNF to not be enough to keep them stable, therefore these nuclei will decay in order to become stable. the type of decay the nuclei will experience depends on the amount of each nucleon in them
where does alpha decay occur
in a large nuclei, with too many of both protons and neutrons
in the equation for alpha decay what happens to the proton number and nucleon number
the proton number decreases by 2
the nucleon number decreases by 4
where does beta minus decay occur
in nuclei which are neutron-rich (have too many neutrons)
what happens the the proton number and nucleon number in the equation for beta minus decay
the proton number increases by 1
the nucleon number stays the same
how did scientists theorize that there is a neutrino in beta minus decay
at first, scientists believed that only an electron was emitted from the nucleus during beta minus decay, however observations of the energy levels of the particles before and after the decay showed that energy was not conserved. this does not follow the principle of conservation of energy, and therefore neutrinos were hypothesized to account fir this, and later they were observed
what is there for every type of particle
an antiparticle
what do antiparticles have the same as the particle
the same rest energy and mass but all other properties are opposite
what is the antiparticle of an electron and neutrino
positron and antineutrino
what do electromagnetic radiation travel in
packets called photons which transfer energy and have no mass
what is the energy of photons directly proportional to
the frequency of electromagnetic radiation
what equation shows that the energy of photons is directly proportional to the electromagnetic radiation
E = hf = (hc/lambda)
what is the value of plancks constant
6.63x10^-34 Js
what is annihilation
is where a particle and its corresponding antiparticle collide, as a result their masses are converted into energy
what is the energy during annihilation released as
is released in the form of two protons moving in opposite directions in order to conserve momentum
what is an application of annihilation and how does it work
is used in a PET scanner
this allows 3D images of the inside of the body to be taken, therefore making medical diagnoses easier. this is done by introducing a positron-emitting radioisotope into the patient, as positrons are released they annihilate with electrons already in the patients system, emitting gamma photons which can easily be detected