nuclear physics yr 10 2026

atomic number

number of protons in the atoms represented by Z

atomic mass

number of protons and neutrons represented by A

protons

subatomic particles with a positive charge

neutrons

subatomic particles with no charge

nucleons

subatomic particles that make the nucleus; protons and neutrons

strong nuclear force

holds nuclei together and is responsible for binding them together

electromagnetic force

force that affects the charged particles by pushing/pulling particles based on their charge

radioactive decay

process where an unstable nucleus decays through alpha, beta or gamma decay

alpha decay

an atomic particle loses an alpha particle (2 protons and 2 neutrons)

beta decay

an atomic particle loses a beta particle (an electron)

gamma decay

an atomic loses energy through gamma waves (electromagnetic waves)

strong nuclear force to stability of nucleus

acts like glue to attract nucleons together, providing nuclear stability

electromagnetic force to stability of nucleus

causes repulsion between atomic particles

binding energy to stability of nucleus

both directly related to each other

when binding energy is high

nucleus is tightly packed and is more stable

when binding energy is low

nuclear stability is low

binding energy to radioactive nuclei

both directly related to each other

when binding energy is high

nucleus is more stable, therefore less radioactive

when binding energy is low

nucleus is less stable therefore more radioactive

alpha radiation

when too much mass in the atom leads to unstable nucleus where atom releases an alpha particle to become more stable

alpha particle

4/2⍺ or 4/2 He

alpha description

heavy and slow; high ionising ability; low penetrating ability

alpha stopped by

paper

beta radiation

when there are too many neutrons, a neutron transforms into a proton and electron, shooting the electron out

beta particle

0/-1β or 0/-1e

beta description

very light and fast (travels at 98% speed of light); medium ionising and penetrating ability

beta stopped by

few layers of aluminium

gamma radiation

when an unstable and excited nucleus, releases gamma rays

gamma particle

electromagnetic wave which has no mass

gamma description

travels at speed of light; no ionising ability; high penetrating ability; may cause other radiation like alpha or beta

gamma stopped by

lead

half-life

time taken for one half of radioactive nuclei to decay

stability of neutrons

depend of ratio of protons to neutrons

if protons are too much

undergo alpha decay

if protons are too less

undergo beta decay

graphs are

exponential and a curve

calculate half life through

N = N0(1/2)^n

fission

when a large atom splits releasing two or more smaller and stable nuclei, fast neutrons and heat energy

fusion

when 2 or more smaller and light nuclei collide together to form one or more different, heavier nuclei and subatomic particles

difference: use different isotopes fission

uses heavier isotopes because they are already under strain, making it easier to split

difference: use different isotopes fusion

use lighter isotopes because they have lower positive charges making it easier to repel them

difference: chain reactions fission

has a chain reaction because every a nucleus splits, releases neutrons which split other nuclei

difference: chain reactions fusion

has no chain reaction because products do not automatically trigger more fusion

difference: amount of isotopes used fission

only can be used by fissile materials which have the ability to split using a slow neutron

difference: amount of isotopes used fusion

thousands can be fused because pressure and heat allow them to repel their natural repulsion

predicting energy changes

find mass defect (products-reactants) and convert it into energy using E = mc2

mass defect

difference between mass of an atom and sum of all the parts of an atom

relates to energy

because directly determines energy released through Einstein's equation and the missing mass is converted into energy

relationship of energy and mass through E = mc2

shows that energy can be converted into mass and vice versa

binding energy

energy required to split a nucleus into its parts

relationship between mass defect and binding energy

directly proportional because binding energy and mass defect are converted through c2 which is approximately the missing mass and energy required

reactor vessel

encases and prevents radiation from escaping, made from alloy steel

control rods

control the number of neutrons involved in fission, contain materials that can absorb neutron like cadmium and boron

fuel rods

long thin aluminium rods containing 98% non-fissile U-235 and 2% fissile U-238

steam generator

hot coolant runs through tubes with water which make the hot tubes boil and turn into steam, made from alloy steel to withstand pressure and heat

moderator

slows down fast moving neutrons, can be made from graphite, heavy water, normal water and carbon dioxide

how nuclear power stations make electricity

inside nuclear reactors, they have controlled nuclear chain reactions which generate massive amount of energy to release a steady amount of heat, releasing energy

controlled reactions

sustain the original effect, used in nuclear power stations, produce a steady continuous amount of energy, use control rods and moderators to capture excess neutrons and regulate the reaction

uncontrolled reactions

magnify the original effect through displaced neutrons, used in nuclear bombs, produce a catastrophic amount of energy, no safety mechanisms to capture excess neutrons or regulate the reaction

advantages of nuclear energy

no carbon emission or greenhouse gases, more energy density where it can produce more through weight than fossil fuels, more reliable and efficient than fossil fuels because it is independant from weather

disadvantages of nuclear energy

toxic nuclear waste requiring permanent storage, high costs with complex constructions usually taking over a decade, facility failures can lead to catastrophic environmental and health issues