Radioactivity

What are the 3 types of radiation?

• What is the meaning of half-life?

• What are the hazards and benefits of nuclear power use

• Describe the structure of a radioisotope and understand its shorthand notation

• Know the nature of radiation, including background radiation

• Know the properties of the three types of radiation, including the composition, charge, mass, and penetrating power

• Balance nuclear equations for radioactive decay

• Know the meaning of half-life and perform calculations

• Derive half-life from a decay curve

Definition of radioactivity

Radioactivity is uncontrollable and spontaneous decay that emits particles and rays.

Definition of half life

Overall, how much it will decay by half of the mass

Even though we can’t predict when a certain particle will decay we can estimate when a certain amount of a particle will decay/

Isotopes are the same element with a different number of neutrons

Radioisotopes are isotopes that are unstable and undergo radioactive decay, releasing energy in the form of radiation.

A stable isotope does not emit radiation, and an unstable one does undergo spontaneous nuclear decay.

Three types of radiation

Alpha particles, Beta particles, and Gamma rays

1. Alpha particles are made up of 2 protons and 2 neutrons, so they are Helium nuclei. They have the most ionizing powere damaging molecules by making them loose electrons. Whereas it has extremely weak penetrating power and is stopped by centimeters of paper.

During alpha decay, a parent nucleus becomes a daughter nucleus by emitting an alpha particle (helium nucleus)

• When an unstable nucleus (the parent nucleus) emits radiation, it releases a daughter nucleus and an alpha particle.

• As a result, the isotope will change into a different element (the daughter nucleus)

• When an alpha particle is emitted from a nucleus:

  • The nucleus loses 2 protons: proton number decreases by 2

  • The nucleus loses 4 nucleons: nucleon number decreases by 4

During beta-minus decay, a neutron in a parent nucleus becomes a proton in a daughter nucleus by emitting a beta-minus particle (an electron) and an anti-electron neutrino

• When a β^- -particle is emitted from a nucleus:

  • The number of protons increases by 1: proton number increases by 1

  • The total number of nucleons stays the same: nucleon number remains the same

Beta particles are fast-moving electrons, move 9/10ths the speed of light (faster than alpha), have lower ionizing power, but higher penetrating power than alpha, and are stopped by aluminium or a centimeter of wood, can travel meters.

Gamma rays

Does not emit particles but emits rays, high energy, travels at the speed of light, lowest ionizing power, but the highest penetrating power, as it is stopped by thick concrete or lead. and travels kilometers

Half-life is a time measurement for how old objects are by calculating the time taken for the specific isotope to fall to half of its original value.

• half the time it takes for a nucleus to decay

• Isotopes: Variants of elements with the same number of protons but different numbers of neutrons, impacting their stability and rate of radioactive decay.