Isotopes and relative atomic mass Flashcards
What is an isotope?
atoms of the same element but different amount of neutrons
What is the relative atomic mass?
average of the mixture of naturally occuring isotopes depending on their abundance
What is a.m.u
atomic mass unit
What are radioisotopes?
isotopes with unstable nuclei
the ____ of the atom is most stable within a certain neutron/proton ratio
nucleus
What is alpha decay?
The nucleus is too heavy thus an alpha particle (2 protons+2 neutrons (helium)) is emitted to become more stable
- atomic number decreases by 2
- atomic mass decreases by 4
What is beta decay?
Nucleus with too many neutrons undergo beta decay
- neutron turns into proton and a beta particle (highly energised electron) gets emitted
- atomic number increases by 1
- atomic mass remains the same
What elements undergo alpha decay?
atoms heavier than 81 neutrons (lead)
What elements undergo beta decay?
atoms with too many neutrons in the nucleus
What is gamma decay?
Nucleus releases energy in the form of gamma radiation to stabilise an excited nucleus
- atomic mass and number stay the same
What is gamma radiation indicated by?
an asterik
*
What elements undergo gamma decay?
elements where the nucleus is in an excited state and needs to return to a ground state
What is the relative penetrating strength of alpha, beta and gamma particles?
a<b<g
alpha is less than beta is less than gamma
What can alpha radiation be stopped by?
paper
What can beta radiation be stopped by?
aluminium
What can gamma radiation be stopped by?
lead
What is the relative ionising strength of alpha, beta and gamma particles?
alpha>beta>gamma
alpha= high
beta= moderate
gamma= low
What is nuclear fission?
nuclei SPLIT apart
What is nuclear fusion?
nuclei join TOGETHER
