Chapter 21 - Nuclear Chemistry Flashcards
Chemical energy is associated with _______.
the making and breaking of chemical bonds
Nuclear energy is _______ in comparison to chemical energy.
enormous
______ % of worldwide energy use comes from nuclear energy.
13%
Nuclear energy is due to changes in the nucleus of atoms _________.
changing them into different atoms
The nucleus is composed of the two ______, protons and neutrons.
nucleons
The number of ____ is the atomic number.
protons
The number of ________ is the mass number.
protons and neutrons together
Define isotope.
each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties
It is not uncommon for some nuclidies of an element to be unstable, or ______.
radioactive
Define radionuclide.
an unstable nuclide of an element
List five types of radioactive decay.
Alpha decay Beta decay Gamma emission Positron emission Electron capture
Define alpha decay.
the loss of an α-particle
Define beta decay.
the loss of a β-particle (a high-speed electron emitted by the nucleus)
Define gamma emission.
Gamma emission is the loss of a γ-ray, which is high-energy radiation that almost always accompanies the loss of a nuclear particle
Define positron.
a particle that has the same mass as, but an opposite charge to, that of an electron
Some nuclei decay by emitting a _____, a particle that has the same mass as, but an opposite charge to, that of an electron.
positron
An electron from the surrounding electron cloud is absorbed into the nucleus during _____.
electron capture
_________ helps keep the nucleus together.
strong nuclear force
Any atom with more than one proton (anything but H) will have _____ between the protons in the nucleus.
repulsion
Neutrons play a key role _____ the nucleus, so the ratio of neutrons to protons is an important factor.
stabilizing
For smaller nuclei (Z ≤ 20), _____ nuclei have a neutron-to-proton ratio
close to 1:1.
stable
As nuclei get _____, it takes a larger number of neutrons to stabilize the nucleus.
larger
Nuclei above the _____ have too many neutrons, so they tend to decay by emitting beta particles
belt of stability
Nuclei below the belt of stability have too many ____, so they tend to become more stable by positron emission or electron capture.
protons
There are _____ stable nuclei with an atomic number greater than 83.
Nuclei with such large atomic numbers tend to decay by _____.
no, alpha emission
List the magic proton numbers.
2, 8, 20, 28, 50, 82
List the magic neutron numbers.
2, 8, 20, 28, 50, 82, 126
Nuclei with an _____ number of protons and neutrons tend to be more stable than those with odd numbers
even
_____ can be induced by accelerating a particle to collide it with the nuclide.
nuclear transmutations
_____ (“atom smashers”) are enormous, having circular tracks with radii that are miles long.
particle accelerators
Radioactive decay is a _______ process.
first order
Half-life is the time required for _____ of a radionuclide sample to decay.
half
_____ is the rate at which a sample decays.
activity
Define Becquerel (Bq).
one desintegration per second
