P7 Radioactivity
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What did Ernest Rutherford discover
Two types of radiation alpha radiation and beta radiation
What does a unstable nucleus atom in a substance do to become stable or less unstable
They will emit alpha beta or gamma radiation
What type of radiation is alpha
a (symbol) two protons and neutrons with a charge of 2+
What type of radiation is beta
Round capital B its made of fast moving electrons with a charge of -1
What type of radiation is gamma
y (symbol) electromagnetic radiation with a charge of 0
What was the plum pudding model
Atoms were thought to contain positively charged matter evenly spread out with electrons buried inside
What was the nuclear model
The fist ideas of electrons sin outer rings around a positive nucleus as alpha particles were emitted facing an element and most particles went through with one in 10000 getting deflected by over 90 degrees
What was Niels Bohrs’ theory
That electrons porbit the nucleus at specific distances and specific energy values or energy levels
In alpha and beta decay what changes
The number of protons and in alpha neutrons aswell
In nuclear equations how are alpha particles represented
4 H because its identical to a helium nucleus 2
How are beta particles represented
0 e because a neutron changes into a proton and electron when emitted the proton stays in the nucleus when there -1 Are to many neutrons and the electron leaves removing a charge but not removing any weight because its so small
When will a neutron be emitted by a nucleus
In radioactive decay this can happen in the upper atmosphere and is caused by a nuclei in the atmosphere absorbing cosmic radiation, because neutrons are uncharged they can pass through substances more easily
What is ionisation
When an object is exposed to ionising radiation and only becomes irratated
What is radioactive contamination
The unwanted process of materials containing radioactive atoms on other materials
What can ionisation do to a living cell
It can damage or kill it and if the cell regenerates damage to the genes in a cell can be passed on if the cell generates more cells
How are alpha particles used in smoke alarms
They send alpha particles into a gap in the circuit of the fire alarm.The alpha particles ionise the air in the gap so there is a current.smoke is detected because it blocks the alpha particles completing the circuit as it acts as a blockade starting the alarm sound.Beta or gamma can be used for this because they don’t create enough ions for this