radioactive decay and stability

radioactive decay

Spontaneous breakdown of an unstable nucleus that releases radiation. Periodic Table: There are about 38 radioactive elements represented.

why radioactive nuclei decay

• Cause: Nuclei have an unstable combination of protons and neutrons.

• Goal: The nucleus undergoes a change to become more stable.

types of radiation emitted during decay

• Emitted: Radiation is released during decay.

• 3 Main Types: Alpha, beta, and gamma.

half life definition

the time taken for half of the radioactive atoms in a sample to decay (can be minutes, days, years or thousands of years)

Half-life vs. Safety (Key relationship)

• Short half-life: Atoms decay more quickly and become safe much faster (loses radioactivity rapidly).

• Long half-life: Atoms decay more slowly and remain radioactive for longer.

Does half-life alone determine how dangerous a source is?

• No. Half-life alone does not determine danger.

• Other critical factors: Radiation type, activity, dose, and exposure.

Ionising radiation (Definition & Damage)

• Definition: Radiation with enough energy to ionise atoms and molecules.

• Mechanism: Passes through matter and interacts with biological molecules (including DNA).

• Cell Impact: Causes changes to cells.

diseases contributed to by ionising radiation

• Cell/Blood: Cancer, leukaemia, and other blood disorders.

• Body: Skin burns and eye cataracts.

radiation uses: sterilisation

Kills microorganisms on surgical instruments (Irradiation = exposing an object to radiation).

radiation uses: cancer treatment

Gamma radiation kills cancerous tumour cells (Goal: limit damage to healthy tissue).

radiation uses: medical imaging

• Mechanism: Radioactive compounds are designed to accumulate in particular tissues.

• Application: Compounds attach to cancer cells to detect tumours

radioscopes

• Radioisotopes: Atoms that undergo this radioactive decay process.