Topic 11 - Nuclear Chemistry Flashcards
(15 cards)
What does radioactive decay involve?
changes in the nuclei of atoms
How can unstable nuclei (radioisotopes) become more stable nuclei?
by giving out alpha, beta or gamma radiation.
Alpha particles (α)
consist of two protons and two neutrons and carry a double positive
charge. They have a range of only a few centimetres in air and are stopped by a piece of paper. They are attracted towards a negatively charged plate.
Beta particles (β)
are electrons ejected from the nucleus of an atom. They can 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.
Gamma rays (γ)
are electromagnetic waves emitted from within the nucleus of an atom.
They can travel great distances in air. They can be stopped by barriers made of materials such as lead or concrete. Gamma rays are not deflected by an electric field.
What is used to write balanced nuclear equations?
nuclide notation.
What are different particles represented as in nuclear equations ?
alpha particle - ⁴₂He
beta particle - ⁰₋₁e
a proton - ¹₁p
a neutron - ¹₀n
What must be equal on both sides of a nuclear equation?
The sum of atomic numbers must be equal
The sum of mass numbers must be equal
What is half-life?
half life is the time for half of the nuclei of a particular isotope to decay
The half-life of a radioisotope is a
is a constant, unaffected by chemical or physical conditions.
What can radioactive isotopes be used for?
radioactive isotopes can be used to date materials
How can the half life of an isotope be determined?
from a graph showing a decay curve
Where do radioisotopes have uses?
radioisotopes have a range of uses in medicine and in industry.
Calculations can be performed using the link between
the number of half-lives, time and
the proportion of a radioisotope remaining.
Given information on the type of radiation emitted and/or half-lives, the
suitability of an isotope for a particular application can be evaluated
