P7 Radioactivity Flashcards
What is a isotope?
Different forms of each element
It has a different amount of protons but the SAME amount of protons
How safe are isotopes?
Each element has about 2 stable form of isotopes
The rest tend to decay into other elements and give out radiation as they try and become more stable. This is known as radioactive decay
What is radioactive decay?
The prosses of which atoms give out radiation to get rid of exces energy to become more stable
What are the 3 types of ionising radiation?
Alpha
Bata
Gama
(Ther are more)
Where does the radiation come from?
The nucleus
What could a atom do whilst decaying?
Give out 1 or more types of radiation
Release a nuetron to rebalnce the number of protons and neutrons
What does ionising radiation make an atom do?
Get rid of an electron (making it into a positive ion)
Give out ionising radiation
What is ionising power?
How easily an atom can get rid of an electron through ionising radiation
What is alpha radiation?
When an alpha particle is emitted from the nucleus
2 protons and 2 neutrons
How far do alpha radiation penentrat?
What will stop it?
Not far. They can only travel through a few cm of air and is absorbed by a piece of paper
How strong/weak is alpha radiation’s ionising power?
Very strong due to it’s size
It is the strongest
What is the name of 2 protons and 2 neutrons?
Helium nuclei
What is Beta radiation?
Fast moving electrons released by the nucleus
What is the mass of a Beta particle?
Virtually no mass
What is the charge of a Beta Particle?
-1
What is the charge of a Alpha particle?
+2
What is the relative mass or an alpha particle?
4
What is the mass of a Beta particle?
1/1836
What is the ionising power of Beta particles?
Moderate
What is the penentration power of a Beta particle?
Moderate
They will travel about a few meters in air but will be absorbed by a sheet of aluminium (around 5mm)
What happens when a Beta particle is emmited from the nucleus?
A nuetron turns into a nucleus
What type of waves are gama?
Electromagnetic waves
What is the penentration power of a Gamma radiation?
Extremly high
It will travel long distances through air and will be absorbed by thick sheets of lead or layers of concreate
What is the ionising power of Gamma radiation?
Low/weak as they tend to no collide with other particles but when they do collode they do damage
What is the mass of a Gamma ray?
0
What is the charge of a Gamma rays?
0
What happens to the atomic number in α radiation
It will decrease by 2
What happens to the atomic mass in α radiation
It decreased by 4
What is the alpha radiation equastsion?
a a-4 4
X = Y + He
b b-2 2
Explain the alpha radiation equasion?
Because alpha radiation emitts 2 protons and 2 neutrons the atomic number goes down by 2 as it looses 2 protons and the atomic mass goes down by 4 as it is loosing the mass of 2 neutrons and 2 protons
How does beta (e) radiation effect the atomic number
Increases by 1
How does beta (e) radiation effect the atomic number?
No effect
Why does the atomic number increase by 1 in beta radiation?
When the electron leaves a neutron is turned into a proton
What is the beta radiation equasion?
a a 0
X = Y + e
b b+1 -1
How does gamma radiation efefct the atomic number and the mas number?
No change
What does gamma radiation do?
Get rid of excess energy from the nucleus
What is the rate of radiation?
It is random
How is radiation measured?
What units?
With a GM tube
Count-rate OR Becquelrels (Bq)
What is the half life?
The amount of time it takes for half the atoms to decay in an radioative substance
It can also be the amount of time it takes for activity to half
What is activity?
The number of unstable nuclei that decay every second
What would you expect to happen to the activity of an atom as time increases?
To decrease as there will be less unstable atoms
What will the activity never equal to?
0
Solve:
Tye initial activity is 640Bq. Calcuate it’s final activity after 2 half lives?
640/2=320
320/2=160
160/640=0.25X100=25%
25%
How can you measure half time with a graph?
You go to the activity axis of the graph and half the top value. Then use a ruler to find out what the time value is. That is it’s half life
If something has a mass of 10g and a half life of 8 days what will the mass be after 8 days?
10/2=5
5g
More advanced maths questions on goodnotes.
Science - Phycics - Module 2 - P7 Radiation - P7 workbook
