Atomic Structure Flashcards
What is the plum pudding model?
A model of the atom where the atom consisted of positively charged sphere with a lot of negative electrons stuck in it.
Proposed by J.J Thomson
What is the nuclear model?
Current model of positively charged nucleus of protons and neutrons, orbited by negatively charged electrons.
Proposed by Ernest Rutherford
What is alpha (α) radiation?
2 neutrons and 2 protons
Same as Helium nucleus.
Atomic No = -2
Mass No = -4
What is the electric charge of alpha radiation?
+2
What is the relative atomic mass of alpha radiation?
4
How penetrating is alpha radiation?
Stopped by paper or a few centimetres of air
How ionising is alpha radiation?
Strongly ionising
What is effect of magnetic field of alpha particle?
Strongly deflected
What is beta (β) radiation?
High energy electron
A neutron changes to a proton
Atomic No. = +1
Mass No. = +0
What is the electric charge of beta radiation?
-1
What is the relative atomic mass of beta radiation?
1/1860
How penetrating is beta radiation?
Stopped by a few millimetres of aluminium
How ionising is is beta radiation?
Weakly ionising
What is the effect of the magnetic field of beta radiation?
Strongly deflected
What is Gamma (y) radiation?
High energy electromagnetic radiation
Atomic No = +0
Mass No = +0
What is the electric charge of gamma radiation?
0
What is the relative atomic mass of gamma radiation?
0
What is the penetrating power of gamma radiation?
Stopped by several centimetres of lead or several metres of concrete
How ionising is gamma radiation?
Very weakly ionising
What is the effect of the magnetic field of gamma radiation?
Not deflected
What is radioactivity?
Some atomic Isotopes are unstable and emit radiation so they become more stable this process is called Radioactive Decay.
What are the 3 types of radiation?
- Alphaα
- Beta β
- Gamma γ
What is ionisation?
When radiation hits an atom it can cause it to lose electrons.
The positively charged atom produced is called an ion, and this process is called ionisation
What is radioactivity measured by/with?
Measured in Becquerel (Bq)
Decay is measured by a Geiger-Muller tube (eg a Geiger Counter)
