Nuclear Chemistry Flashcards
Transformations of atomic nuclei are fittingly called _____ reactions. Some spontaneous reactions occur at room temperature emits ___ and are said to be _____
nuclear reactions; radiation; radioactive
Define nucleons
protons and neutrons
All atoms of a given element have the same number of ____; this number is the element’s _____.
protons; atomic number
Atoms of a given element can have different numbers of _____, which means they can have different _____.
neutrons; mass numbers
Define mass number
total number of nucleons (protons + neutrons) in the nucleus
Atoms with the same atomic number but different mass numbers are known as ____
isotopes
Three naturally occurring isotopes of uranium. Rank in increasing natural abundances
uranium-238 (99.3%)
uranium-235 (0.7%)
uranium-234 (trace amount)
Different isotopes of an element have different ____ and different _____
natural abundances and stabilities
a nucleus containing a specified number of protons and neutrons
nuclide
Nuclides that are radioactive are called ____, and atoms containing these nuclei are called ____
radionuclides; radioisotopes
____ are unstable and spontaneously emit particles and electromagnetic radiation
Radionuclides
How did unstable nucleus transform into a more stable one?
Emission of radiation that carries the excess energy
The ___ are known as alpha (α) particles. Radioactive decay that involves this particle is called ___
helium-4 particles; alpha decay or alpha emission
Radioactive decay was discovered by ____ in ____. He saw that photographic plates developed ____ when _____
Antoine Henri Becquerel in 1896
bright spots when exposed to uranium metals
high-speed electrons emitted by an unstable nucleus
beta β particles
In beta particles, the superscript 0 indicates that ______. The subscript -1 represents the _____ of the beta particle, which is opposite that of the proton.
the mass of the electron is exceedingly small relative to the mass of a nucleon
negative charge
beta emission is equivalent to the conversion of a ___ to a ____
neutron to a proton
consists of high-energy photons (electromagnetic radiation of very short wavelength) that changes neither the atomic number nor the mass number of a nucleus
gamma radiation
a particle that has the same mass as an electron but opposite charge
positron
has the effect of converting a proton to a neutron, thereby decreasing the atomic number of the nucleus by 1 while not changing the mass number
positron emission
capture by the nucleus of an electron from the electron cloud surrounding the nucleus (electron is consumed)
electron capture
Rank in increasing penetrating power
neutron, gamma ray, alpha ray, beta ray
alpha ray, beta ray, gamma ray, neutron
