Topic 7: Nuclear Chemistry

What is radiation?

The release of particles or rays from an unstable nuclei in an isotope to help make the atom more stable.

List the three types of radiation

Alpha particles, Beta particles and gamma waves

Explain an alpha particle

its the heaviest particle and can travel a few centimetres in the air.

What are alpha particles made up of and why?

Helium nuclei which caries a double positive charge because it contains 2 protons and neutrons

Explain a beta particle

light weight particles made up of single, very high energy electron and can travel over a metre in air.

Explain gamma waves

a form of electromagnetic radiation and come from the nucleus, very high energy waves that can travel very long distances in air and penetrate deep into even very dense substances.

What happens to an alpha particle when its passed through an electric field and why

they have a positive charge so they are deflected to the negative side

What happens to a beta particle when its passed through an electric field and why

they are negatively charged so they are deflected to the positive side

What happens to gamma rays when its passed through an electric field and why

they are not charged so they pass through unaffected

What can stop an alpha particle?

a thin piece of paper

What can stop a beta particle?

few mm of lead or aluminum

What can stop gamma rays?

thick lead or thicker concrete

What is another word to describe the breakdown of unstable nuclei?

Decay

What is it called when protons and neutrons are on the left hand side of a nuclear decay series?

its captured

What is it called when protons and neutrons are on the right hand side of a nuclear decay series?

its emitted

When beta is emitted the mass number is unaffected, why?

A neutron has been changed into a protons and en electron.

When is gamma waves emitted ?

At the same time when beta particles are emitted.

What is a half life?

the amount of time it takes for an element to lose half of its radioactivity

What is half life unaffected by?

physical conditions and chemical changes

What is dating?

using a radioisotope to find out how old an object containing the substance is due to its unique and constant half life

Give the particle emitted, half life and use of Cobalt-60

Gamma, 5 years, kills cancerous cells

Give the particle emitted, half life and use of Caesium-137

Beta, 30 years, Thickness Gauging

Give the particle emitted, half life and use of Iodine-131

Beta, 8 years, Diagnosing and treating thyroid problems

Give the particle emitted, half life and use of Americium-241

Alpha, 432 years, smoke detectors