1. Particles Flashcards
Name the two nucleons that make up an atoms nucleus.
Protons and Neutrons
What is the name of the particle that orbits around the atom in energy shells?
Electrons
Order the 3 particles of an atom in order of highest mass to lowest.
Neutron (1.67(5) x 10^-27), Proton (1.67(3) x 10^-27), Electron (9.11x10^-31)
Which atomic particle has a relative charge of +1.
Proton
Which of the atomic particles is neutrally charged?
Neutron
What is the proton number?
Sometime known as the atomic number, and it is the number of protons in the atoms nucleus. This number determines what element it is.
In a neutral atom, if the atom had 6 protons, how many electrons are there?
6 electrons
What is the nucleon number?
It is the total number of neutrons and protons in the nucleus. Also known as the mass number.
If carbon has a nucleon number of 12 and a proton number of 6, how many neutrons does it have?
12 - 6 = 6 neutrons
Define isotopes.
Atoms with the same number of protons but different numbers of neutrons. This means the atom remains the same element but the mass of the nucleus changes.
What does the number of neutrons in an atom affect in the nucleus?
It’s stability. Unstable nuclei may be radioactive and decay over time to become more stable.
Name a use of radioactive isotopes.
Used to find out how old objects are. All living things contain the same percentage of radioactive carbon-14 taken from the atmosphere. This percentage decreases when the thing dies, due to decay. The age can be approximated for dead organic matter.
Define specific charge.
It is the ratio of a particles charge to its mass.
What is the unit of specific charge?
C/kg
What is the specific charge of a proton?
SC = charge/mass => (1.60 x 10^-19)/(1.67 x 10^-27)
= (9.58 x 10^7)
Name the four fundamental forces.
Strong nuclear, weak nuclear, electromagnetic and gravitational.
What is the strong nuclear force?
An attractive force that opposes the the electromagnetic force, holding nucleons in the nucleus.
What force is stronger, strong nuclear or electromagnetic?
Strong Nuclear.
Does the strong nuclear force have a very large range of a very short range?
Very short range, it can only hold nucleons together that are separated by up to a few femtometres.
What does 1 femtometre equal in metres?
1fm = 1 x 10^-15 m
The strength of the _________ attractive force quickly falls beyond a couple of femtometres.
Strong nuclear
When is the strong nuclear force repulsive?
At very small separation between the nucleons, so that the nucleus doesn’t crush to a point.
Does alpha emission only occur in very large nuclei or very small nuclei?
Very large. This is because the nucleus is so large for the strong force to keep the nucleons together.
Give an example of a element that can emit alpha radiation.
Uranium and radium.
When an alpha particle is emitted…
The proton number decreases by two and the nucleon number decreases by four.
An alpha particle is made up of…
Two protons and two neutrons. (Helium nucleus)
Do alpha particles have a greater range than beta particles.
No, beta has a greater range.
What is the link between alpha particles and a cloud chamber?
The short range of the alpha particles can be seen as tracks in the cloud chamber.
Does beta minus decay happen in neutron-rich nuclei or proton-rich nuclei?
Neutron-rich nuclei. Neutron in the atom is changed into a proton when the beta minus particle is released.
When a beta minus particle is emitted…
The proton number increases by one and the nucleon number remains the same.
What other molecule is emitted during beta minus decay?
Electron Antineutrino.
What is a beta minus particle?
A fast moving electron.
What does the antineutrino conserve in this process?
Energy and momentum.
Name the electromagnetic wave which has the highest frequency.
Gamma rays.
Name the electromagnetic wave that has the highest wavelength.
Radio waves.
Give the equation that links speed (c) , frequency (f) and wavelength (w)
f = c/w
Is electromagnetic waves a transverse or longitudinal wave?
Transverse.
What is the E in the equation: E = hf
The energy of a photon, which is dependent on the frequency.
Define antiparticle.
An antiparticle has the same mass and rest energy as its corresponding particle but has an opposite charge.
What is the antiparticle of an proton?
Antiproton
What is the relative charge of a positron?
+1
Do neutrinos have an antiparticle?
Yes, Anti-neutrino
What is the rest energy of a neutrino?
0
Does a neutron and an anti-neutron have the same mass and rest energy?
Yes.
The rest energy of a particle is just the ‘energy equivalent’ of a particle’s ________
Mass
What is the unit of rest energy?
Electron Volts (or joules)