P6 Flashcards
Describe the charge of the atom
An equal number of protons and electrons, to Crete an overall charge of 0
What are ions
Different number of electrons
What are isotopes?
Different number of neutrons , but same element (atomic number)
What is an unstable nucleus?
Has too much energy and must get rid of it
What is a radio active substance?
A substance that becomes stable by emitting radiation
What does is mean to be ‘unstable’?
Too many protons and /or neutrons in a nucleus to be nicely held together.
What are the 3 different forms of radiation, and their charge?
Alpha ➡️ 2+
Beta➡️ 1-
Gamma➡️ 0
Describe alpha radiation
A particle
2 protons and 2 neutrons
Heavily ionising
Stopped by paper/skin
Very slow because is heavy
Up to few cm range
Describe beta radiation:
A fast moving electron
Stopped by thin aluminium
Moderately ionising
Fast
Up to 1m
Describe gamma radiation
A wave
High energy electromagnetic waves
Travels at the speed of light
Lightly ionising
Stopped by thick lead
Unlimbered range in air
What is ionisation?
Makes ions within the body, this is bad because those damages cells become highly reactive and replicate within the body creating tumours .
Why is penetrating power the opposite of ionising power?
If you penetrate though substances , you simply pass them- you don’t ionise them
Why does beta experience a greater deflection than alpha in an electromagnet field?
F=M✖️ A
Alpha has greater mass and will therefore result in a smaller acceleration
What is a Geiger counter?
A instrument used to detect and measure ionising radiation.
What decides the radioactivity a source can emit?
The heavier , the more likely it is to emit all three types
What happens during gamma decay?
The nucleus stays the same but inky loses energy
What happens during alpha decay?
The nucleus loses two protons and two neutrons, therefore the new nucleus has a lower amount of protons and neutrons
4
2
What happens during beta decay?
A neurones turns into one electron and one proton. It keeps the proton in the nucleus, but let’s go of an electron.This decreases the number of neutrons by 1, and increases the number of protons by 1.
0
-1
Can you predict when a single unstable nucleus will decay?
No radioactive decay is a random process
What is half life?
The time taken for half of the unstable nuclei in a radioactive substance to decay.
Time taken for activity to half