Flashcards in Atomic and Nuclear Physics Deck (118)
Describe the model of the atom:
There is a tiny, dense, positively charged nucleus at the centre of 'empty space' with an electron cloud
To what order is the diameter of the atom?
To what order is the diameter of the nucleus?
What is the charge of a proton?
+1.6 x 10^-19 C
What is the charge of a neutron?
What is the charge of a electron?
-1.6 x 10^-19 C
How would an isotope be defined?
A form of an element
that has the same number of protons
but a different number of neutrons
compared to the most abundant form.
What is the nucleon number?
The number of protons and neutrons in the nucleus of an atom
A radioactive substance contains unstable nuclei. What do unstable nuclei have?
An inbalance of energy between the nucleons
How does a particle become more stable?
By improving the balance of energy between the nucleons.
How is the balance of energy between the nucleons improved?
By emitting energy from the nucleus in the form of:
-Electromagnetic radiation (carried by photons)
Alpha Decay is a mechanism of radioactive decay, what does it do?
Ejects two protons and two neutrons (as a single particle) from the nucleus
What is Beta decay?
The emission of an electron from the nucleus- a neutron turns into a proton and emits an electron
What is gamma decay?
The emission of high frequency (high energy) electromagnetic radiation from the nucleus
What does ionising ability indicate?
How much each radiation type interacts with matter
What is the relative charge of an alpha particle?
+2 (two protons)
What is the relative charge of a beta particle?
-1 (one electron)
What is the relative charge of a gamma particle?
What is the relative mass if an alpha particle?
What is the relative mass of a beta particle?
What is the relative mass of a gamma particle?
What is the range in air for alpha radiation?
a few centimetres
What is the range in air for beta radiation?
of the order of a metre
What is the range in air for gamma radiation?
What is alpha radiation stopped by?
What is beta radiation stopped by?
a few millimetres of aluminium
What is gamma radiation stopped by?
Many centimetres of lead or metres of concrete (sometimes combination)
What is the ionising ability of alpha radiation?
What is the ionising ability of beta radiation?