Nucleon- particles that reside within the nucleus (proton and neutron)
Isotopes- Forms of an element with the same proton number but different nucleon numbers
Anti particle- A 'Mirror image' of a particle with identical mass but opposite charge
Annihilation- The conversion of mass of a particle and its antiparticle to a pair of photons of electromagentic radiation
Pair production- The process of a photon of electromagnetic energy is converted to a pair of particles
Neutrino- fundamental particle with no charge
Exchange particle- Virtual particle, may exist for a very short time and is a force mediator
Conservation of charge- total charge after reaction is smae as total charge before reaction
Inside the nucleus
A neutral atom has no net charge, this is due to the number of protons being balanced by the number of electrons orbitting the atom.
Holding the nucleus together is positive charges repelling each other, and at short distances electrostatic forces pushing the nucleus apart. Another that acts inside the nucleus known as the strong force, it has a short range and no effect on seperations greater than 5fm, it is an attractive force until the separation is less than 1fm (it then becomes v repulsive). Its overall efect is to pull nucleus together, however the repulsion keeps it from collapsing.
Isotopes are forms of an element with the same proton number but different nucleon numbers
Different isotopes of an element have identical chemical behaviour as their atoms have same number of electrons.
Isotopes also have same number of protons in their nucleus, difference is simply number of neutrons (makes some isotopes heavier than others)
The opposite process to annihilation is pair production where matter is produced from energy.
In pair production two particles are always created, one being a conventional particle and one being its antimatter twin. After pair production there is always one positive and one negative particle so the overall charge is 0
Probably the most abundant particles in universe, outnumber protons and neutrons. They are emitted by radioactive nuclei and form nuclear reactions.
Neutrinos and antineutrinos are difficult to detect due to their lack of charge. Neutrinos interract with other matter very weakly.
Neutrino is a fundamental particle which carries no charge and mass that is much less than that of an electron.
Forces that hold various particcles in the nucleus together in an atom
Gravity- Infinite range, acts in all particles, on an atomic scale it has negligible influence as it the weakest fundamental force
Electromagnetic force- Acts between all charged particles, holds atoms and molecules together
Weak interraction- Acts between all particles over short range, responsible for radioactive decay
Strong interraction- the strong interraction holds neuclei together, it acts between hadrons (neutrons or protons) short range, the strong force is not felt by leptopns
Classification of particles
Current theories suggest there are only 3 families of fundamental particles
12 different members of lepton family, three being types of electrons, (electron muon and tau) three types of neutrinos and all their antiparticles
All leptons are fundamental particles
The Muon- close relative of the electron, carries same charge as electron but possesses a mass 207 times bigger
Leptons and antileptons are fundamental particles
Three charged leptons; electron, muon and tau
each of these has an associuated nutrino
each has an antiparticle
Possess a much greater mass than leptons (Pi mesons, Kaons, delta mesons)
They are divided into 2 groups
Baryons; proton, neutron and their antiparticles
Mesons; pi/pi meson- takes 3 forms (positive, negative and uncharged), k meson/kaon
Quarks and antiquarks
All hadrons are composed of smaller constiuents called Quarks
There are 3 different types of quark; up, down and strange alongside their antiquarks
Baryons are combinations of three quarks
Antibaryons consist of three antiquarks
Mesons are composed of a quark and an antiquark
Specific charge is calculated by dividing charge by mass, its units are C/KG-1