Flashcards in Particles and Radiation Deck (181)
What is a nucleon?
A particle in the nucleus (protons and neutrons)
What is the relative mass of an electron?
What is the proton number?
Number of protons in the nucleus
What defines what an element is?
The number of protons
What do an element's reactions and chemical behaviour depend on?
Number and arrangement of electrons
What is the mass number?
Number of protons and neutrons in the nucleus
In physics, what does 'specific' mean?
Per unit mass
What is the specific charge of a particle?
The ratio of its charge to its mass
What is the SI units of specific charge?
What is the equation for specific charge?
Specific charge = Charge / Mass
What is a fundamental particle?
A particle that cannot be split up into anything smaller, such an electron
What is an isotope?
An atom of an element with the same number of protons, but a different number of neutrons
What does changing the number of neutrons of an atom affect?
The stability of the nucleus
In general, the greater the number of neutrons compared with the number of protons...?
The more unstable the nucleus is
What do unstable nuclei do?
Decay to make themselves more stable
What isotopic data?
The relative amounts of isotopes in a substance
What is the electromagnetic force?
A fundamental force that causes interactions between charged particles
What does the electromagnetic force cause in the nucleus?
The positively charged protons to repel each other
What does the gravitational force in the nucleus cause?
All the nucleons in the nucleus to attract each other due to their mass
Which is a bigger force in the nucleus, the repulsion from the electromagnetic force or attraction from the gravitational force?
The repulsion from the electromagnetic force
What is the strong nuclear force?
A fundamental force with a short range which is attractive at short separations, but repulsive at very small separations
What is the strong nuclear force responsible for?
The stability of the atom
What are interactions that use the strong nuclear force called?
What separation of nucleons is the strong nuclear force repulsive for?
Less than 0.5 fm (5x10^-16 m)
Describe the strong nuclear force once the nucleon separation has increased past 0.5 fm?
The strong nuclear force becomes attractive, reaching a maximum attractive value, the falling rapidly to zero after about 3 fm (3x10^-15)
What is nuclear decay?
When unstable nuclei will emit particles to become more stable
What is an alpha particle?
The nucleus of a helium atom
Alpha decay can only happen in...?
Very large atoms with more than 82 protons
Why are very large atoms, such as uranium, very unstable?
Because they're so big that the strong nuclear charge can't keep them stable