Unit: 2 - nuclear chemistry Flashcards
(8 cards)
What is radioactive decay?
radioactive decay involves changes in the nuclei of atoms;
unstable nuclei (radioisotopes) can become more stable nuclei by giving out alpha, beta or gamma radiation.
What is alpha decay?
alpha particles (α) consist of two protons and two neutrons, and carry a double positive charge;
alpha particles have a range of only a few centimetres in air and are stopped by a piece of paper;
alpha particles will be attracted towards a negatively charged plate.
What is beta decay?
beta particles (β) are electrons ejected from the nucleus of an atom;
beta particles are able to travel over a metre in air but can be stopped by a thin sheet of aluminium;
beta particles will be attracted towards a positively charged plate.
What is gamma rays?
gamma rays (γ) are electromagnetic waves emitted from within the nucleus of an atom;
gamma rays are able to travel great distances in air;
gamma rays can be stopped by barriers made of materials such as lead or concrete;
gamma rays are not deflected by an electric field.
What are the nuclear equation formulas?
Nuclear equations:
balanced nuclear equations can be written using nuclide notation;
in nuclear equations:
an alpha particle can be represented as 4/2He
a beta particle can be represented as 0/−1e
a proton can be represented as 1/1p
a neutron can be represented as 1/0n
(The formatting is off, please look at scholar for the proper formatting just didn’t get formatted well here, i added slashes as a fractional way of representing it but don’t use it for the exams)
What is half life?
half-life is the time taken for half of the nuclei of a particular isotope to decay;
the half-life of an isotope is a constant, unaffected by chemical or physical conditions;
the half-life of an isotope can be determined from a graph showing a decay curve;
calculations can be performed using the link between the number of half-lives, time and the proportion of a radioisotope remaining.
What is the use of radioisotopes?
radioisotopes have a range of uses in medicine and in industry;
radioactive isotopes can be used to date materials;
given information on the type of radiation emitted and/or half-lives, the suitability of an isotope for a particular application can be evaluated;
you do not need to be able to name the isotope used in a particular application.
What are the rules of the nuclear chemistry reaction/formulas?
the sum of the atomic numbers on the left of the reaction arrow is equal to the sum of the atomic numbers on the right of the reaction number;
the sum of the mass numbers on the left of the reaction arrow is equal to the sum of the mass numbers on the right of the reaction number.
