Chapter 4a Flashcards
Fundamental force
Irreduceable force all other forces can be derived from it
Isotope
One two or more possible forms of atomic elements wich each have different mass and amount of neutrons
Neutron v nucleon
Subatomic particle found in the nucleus with no electric charge v proton or neutron found in an atoms nucleons
Proton v quark
Subatomic particle found in the nucelous with positive electric charge v fundamental particle which neutrons and protons are made of
Radioactive decay
Process of an atomic nucleus becoming more stable by losing energy and emmiting particles or protons
Radioisotopes
Isotope that will undergo radioactive decay
Strong force v weak force
Fundamental force that holds quarks togethor to form neuclons and holds nucleons togethor within the nucleus v
Fundamental force responsible for beta decay by changing property of quark
Nuclear instability causes
To many protons per neutron
Too many neutrons per proton
Too large (over 84 protons or more)
When is an isotope stable when it has 20 or less protons
Equal protons and neutrons
More than 20 protons in isotope neeed what to be stable
More neutrons then protons to counteract electrostatic repulsion and make isotope stable
Nuclear stability
A nucleus will be stable when the attractive strong force contribution is large enough
to sufficiently counteract the repulsive electrostatic force contribution, and the
nucleons do not have enough energy to undergo nuclear reactions.
Theory and applications
Nuclear stability is a balancing act between the strong and electrostatic forces,
and is influenced by the ratio of protons and neutrons, as well as overall nucleus
size.
How forced make nuclei stable or unstable
We say nuclei are usually more stable the higher their binding energy per nucleon
is, a concept which is explored in Lesson 5A. Isotopes will only ever spontaneously
decay (to become a different element or isotope) if the decay would increase the
overall binding energy. In general, the easier it is for an isotope to decay, the more
unstable it is. The level of isotope stability is influenced by the attractive and
repulsive forces in the nucleus, and the nuclear processes available to increase the
overall binding energy, some of which are discussed in Lessons 4C and 5A.
Stable isotopes usually require the strong force to be slightly stronger than the
electrostatic force within the nucleus. This means the nucleus is more attracted
to itself than it is repelled by itself, and therefore has a higher binding energy per
nucleon, making it less likely to decay.
Effect of adding nucleons to atomic nuclei with more than 20protons
Change in electrostatic forces: if proton is added a larg additional repulsion force from electrostatic repulsion to all other protons in nucleus, if neutrone added none change
Change in strong nuclear forces: if proton added Small additional attractive force
from strong force attraction to
nucleons close to it , if neutron added
Small additional attractive force
from strong force attraction to nucleons close to it
Overall effect on forces: added proton ,
Larger increase in repulsion forces within nucleus, if neutron added smaller increase in attractive forces within nucleous
What happens with forces in nuclei
Strong force attracts all nucleons that are close to eachother, electrostatic force repelling all protons in the nucleous from one another
Why are strong and weak forces important
The strong and the weak nuclear forces are each vital for the universe and Earth to
exist as it does. The strong force makes it possible for protons, neutrons, and atoms
to exist in the first place, and the weak force makes it possible for the Sun and nuclear reactors to produce energy
