Radioactivity - 17

A positively charged nucleus and negatively charged electrons

It is a spontaenous and random process by which the unstable atomic nucleus loses its energy by emission of electromagnetic radiation of particle(s).

It emits an a-particle aka helium and the nucleon number decreases by 4 while the proton number decreases by 2. The atom given out is $^4_2He$

It emits a b-particle aka an electron and the nucleon number remains the same while the proton number increases by 1. The atom given out is $_{-1}^0e$

When a nucleus undergoes alpha or beta decay, gamma radiation is also emitted represented by $^0_0r$

Alpha (stopped by paper) -> Beta (stopped by metal) -> Gamma (stopped by lead)

Gamma -> Beta -> Alpha

Refers to the ability to remove electrons from atoms to form ions

Refers to an environment where no radioactive source has been deliberately introduced

Bacqueral (Bq) measued by a GM counter

Remove all known radioactive sources. Start the counter and the stopwatch. Stop the counter after 10 minutes and record the number of counts. Calculate number of counts per minute by dividing by 10. Repeat your measurement and calculate an average value.

The time taken for half the nuclei of a radioactive nuclide to decay

It can penetrate skin causing “beta burns”

They are electrically charged and can interact strongly with biological cells and tissue, causing damage.

When radioactive substances are absorbed in excessive amounts, they can cause cancers and cause organisms (such as human, animals and plants) to suffer from mutations, stunted growth and / or reproductive defects.

Gamma rays from radioactive source are directed at the brain to destroy brain tumours in gamma knife surgery. But due to the long half-lives, only a small quantity is needed over a long treatment time.

Isotope Iodine-131 is used in treating thyroid disorder. A small amount can destroy thyroid cells and cancer cells. It has short half-lives so it will not remain the body for long.

Isotope, amaericium-241 is used in smoke detectors. α-particles have high ionizing ability, when they are emitted and fall on the detector, current flows in the detector. But smoke that enters the detector absorbs radiation and disrupts the flow of current.