Nuclear Reactions

nucleons

protons and neutrons

isotopes

element with same number of protons but different number of neutrons

^A_ZX

Z= atomic number

A= mass number

X= element symbol

mass defect

when nucleons come together to form a nucleus and some mass is lost and converted to binding energy that is released

*note: the mass defect is NOT large

E = ∆mc²

E= binding energy

∆m= mass defect

c= speed of light

binding energy

measure of the energy required to break apart the nucleus into individual components (protons and neutrons) or the energy released when the nucleus forms from its individual components

nuclear fission

occurs when heavy nucleus collides with a neutron and splits into two smaller atoms, releasing neutrons and energy in the process

*proton and mass number are conserved

nuclear fusion

when two or more lighter nuclei fuse together into one larger nucleus, releasing energy in the process

*proton and mass number are conserved

alpha decay

release of an alpha particle (2 protons and 2 neutrons) or ⁴₂He

occurs for heavier atoms to decrease mass

mass number is decreased by 4 and atomic number is decreased by 2

least penetrating rays

beta plus decay/positron decay

release of a positron of positive charge from a proton that turns into a neutron

mass number is not affected but atomic number decreases by 1

beta minus decay

release of an electron and neutron transforms into a positive charge

mass number is unaffected but atomic number increases by 1

electron capture

proton captures an electron from innermost shell and combines to form a neutron

mass number is unaffected but atomic number decreases by 1

gamma decay

unstable nuclei dissipates its excess energy to become more stable and low-energy → releases gamma rays

mass and atomic number are unaffected but a * symbol indicates a high-energy state

most penetrating rays

half-life

time it takes for half of the original amount of parent isotope to decay into daughter isotope

M_f= M_i(1/2)ⁿ

radioactive decay

A(t)= A_oe^=kt

A(1)= final quantity

A_o = initial decay

k= decay constant

t= time passed