Nat 5 - Radiation

Front

What is radioactive decay?

Back

Radioactive decay involves changes in the nuclei of atoms. Unstable nuclei (radioisotopes) can become more stable by giving out alpha, beta, or gamma radiation.

Front

What are alpha particles?

Back

Alpha particles (α) consist of two protons and two neutrons and carry a double positive charge. They have a range of only a few centimetres in air and are stopped by a piece of paper. Alpha particles are attracted towards a negatively charged plate.

Front

What are beta particles?

Back

Beta particles (β) are electrons ejected from the nucleus of an atom. They can travel over a metre in air but can be stopped by a thin sheet of aluminium. Beta particles are attracted towards a positively charged plate.

Front

What are gamma rays?

Back

Gamma rays (γ) are electromagnetic waves emitted from within the nucleus of an atom. They can travel great distances in air and can be stopped by barriers made of materials such as lead or concrete. Gamma rays are not deflected by an electric field.

Front

How are alpha particles represented in nuclear equations?

Back

An alpha particle can be represented as ⁴₂He in nuclear equations.

Front

How are beta particles represented in nuclear equations?

Back

A beta particle can be represented as ⁰₋₁e in nuclear equations.

Front

How is a proton represented in nuclear equations?

Back

A proton can be represented as ¹₁p in nuclear equations.

Front

How is a neutron represented in nuclear equations?

Back

A neutron can be represented as ¹₀n in nuclear equations.

Front

What must be balanced in nuclear equations?

Back

In nuclear equations, the sum of the atomic numbers and the sum of the mass numbers on the left of the reaction arrow must equal those on the right.

Front

What is half-life?

Back

Half-life is the time for half of the nuclei of a particular isotope to decay. It is a constant, unaffected by chemical or physical conditions.