OCR Gateway Additional Science B Higher P4- What is radioactivity?

What do radioactive substances emit?

Alpha, beta and gamma radiation

What does nuclear radiation cause?

Ionisation of of atoms

Why can't we predict when a nucleus will decay?

Its random process

Why will the average count rate on the geiger muller counter be the same?

There are so many nuclei in a radioactive isotope

What are radioactive nuclei like?

Large and unstable and cant be held strongly enough in the nucleus.

What causes a nucleus to become unstable?

Adding or taking away too many neutrons

What is the half life?

The time it takes half of a radioactive nucleus to decay and it cant be changed

What is a nucleon?

Protons and neutrons

What happens to radioactivity of a substance overtime?

It decreases because overtime more and more of the nucleus decays

What happens to the radioactive nucleus when it has decayed?

It changes to another element

What are alpha particles made of?

Helium nuclei with helium gas around it and consists of 2 protons and 2 neutrons adn has a very large mass and best ionisers

What is a beta particle?

A high speed electron with a very small mass

What charge is an alpha particle?

Positive charge

What charge is a beta particle?

Negative charge

Similarities between x rays and gamma ray

Both electromagnetic waves, high frequency, both ionising, both used in medical treatment, both very penetrating, both similar wavelengths.

How are gamma rays produced?

Randon nuclear decay

What is gamma

An electromagnetic wave

What happens during alpha decay?

Mass number decreases by 4 and nucleus has 2 fewer neutrons and 2 fewer protons. Atomic number decreases by 2.A new element…