| What are weak nuclear force | interaction that causes β-decay, in which a hadron changes to a different hadron with emission of a lepton and an antilepton |
| What are weak nuclear force | interaction that causes β-decay, in which a hadron changes to a different hadron with emission of a lepton and an antilepton |
| What are weak nuclear force | interaction that causes β-decay, in which a hadron changes to a different hadron with emission of a lepton and an antilepton |
| Electron has a mass of approximately ............ and a charge of ....................... | 9.11 x 10⁻³¹ kg (mₑ)
-1.60 x 10⁻¹⁹ C (-e) |
| What is the radius of a proton/neutron | 10⁻¹⁵ m |
| What is the radius of a nucleus | 10⁻¹⁵m to 10⁻¹⁴ m |
| What is the radius of an atom? | 10⁻¹⁰ m |
| What is the approximate size of a molecule | 10⁻¹⁰ m to 10⁻ ⁶m |
| What is the mass of a proton? | 1.67 x 10⁻²⁷ kg |
| What are nucleons | Protons and neutrons in a nucleus are collectively called nucleons |
| What is the nucleon number | Total number of nucleons in a nucleus |
| Unit used to measure masses at this level is | Unified atomic mass unit (u) |
| 1u is defined as being | one twelfth of the mass of a carbon-12 atom. |
| What are Isotopes | nuclei of the same element with different numbers of neutrons but same number of protons |
| What is an ion | If an atom gains or loses an electron , it is no longer electrically neutral and is called an ion |
| What determines the chemical properties of the atom | number of protons |
| Who is credited with the discovery of radioactivity | French physicist Henri Becquerel in 1896 |
| What are the 3 types of radiation commonly emitted by radioactive substances | alpha ⍺
beta β
gamma ? |
| What are some properties of ⍺-radiation | 1. Slow moving large particles
2. Interact with atoms in the medium through which they are travelling, causing ionisation within the medium
3. Lose energy rapidly, not very penetrative and have very short range |
| When does β-decay occur | when there is an imbalance of protons and neutrons in the nucleus, usually too many neutrons |
| What is a general term for antiparticles | antimatter |
| What conclusion could be drawn from the observation that all the ⍺-particles tracks were the same length | It suggests that they all have the same initial kinetic energy |
| What is 1 electronvolt | Energy transferred when an electron through a potential difference of one volt |
| 1 electronvolt is how many Joules | 1.60 x 10⁻¹⁹ J |
| Particle given off when a positron is emitted is called ... | electron neutrino |
| New particles were found in 2 ways | 1. Looking at cosmic rays, which are particles that arrive at the earth from outer space
2. Looking at the particles produced by high-energy collisions in particle accelerators |
| Sub-atomic particles are divided into 2 families, | Leptons
- such as electrons and neutrinos
- particles that are unaffected by the strong nuclear force
Hadrons
- Such as protons and neutrons
- All particles that are unaffected by the strong nuclear force |
| What are the 2 ways in which quarks can combine to produce hadrons | 1. three quarks make up a class of hadrons called baryons
2. A quark and an antiquark make up a class of hadron called mesons |
| What are Antimatter | materials made up of antiparticles of the corresponding particles of ordinary matter. All particles have an antiparticles, which has the same mass as the particles but the opposite charge |
| What are Quarks | particles that make up hadrons |
| What are the 6 flavours of quark | up, down, strange, charm, top and bottom |
| Quarks have charges of ..... or... | +⅔ e or -⅓ e |
| What is strong nuclear force | The force that acts between quarks and hold the nucleus together |
| What are Leptons (such as electrons ) | are particles that are unaffected by the strong nuclear force |
| What are Hadrons (such as the neutrons ) | Are particles that consist of quarks and hence are affected by the strong nuclear force. |
| What are weak nuclear force | interaction that causes β-decay, in which a hadron changes to a different hadron with emission of a lepton and an antilepton |
