The radius of an atom is 1 x 10(-10) and the nucleus is about 1/10000 of this
Electrons can change energy levels when an atom ❌ electromagnetic radiation so the electrons moves from a ❌ energy level to a ❌ on. If the atom ❌ electromagnetic radiation so the electron returns to its ❌ energy level
What does the mass number represent?
Protons and Neutrons
Protons and Electrons
Neutrons
Electrons
Protons
Isotopes are the same element but with a different number of
Ancient Greeks->1897->Plum pudding model->Alpha scattering experiment->Nuclear model->Niels Bohr->James Chadwick
Some isotopes have an ❌ nucleus so to become ❌ the nucleus gives out ❌ - radioactive decay ( a ❌ process)
The rate at which a source of ❌ nuclei ❌. Which is measured using a ❌-muller tube.
Alpha particles—>
2 protons + 2 neutrons
An electrons which is ejected form the nucleus at a very high speed and formed in the nucleus when a neutron changes into a proton and an electron
A type of electromagnetic radiation from the nucleus
A neutron
Beta particle—>
An electron which is ejected from the nucleus at a very high speed. Formed inside the nucleus when a neutron changes into a proton and an electron
Gamma radiation—>
2 protons + 2 nucleus
An electron which is ejected from the nucleus at a very high speed. Formed inside the nucleus when a neutron changes into a proton and an electron.
Neutron
Nuclear equations- alpha decay, atomic number decreases by 2 4 1( 2, 4, 1 ) and the mass number by 4 6 1 2( 4, 6, 1, 2 )
Nuclear equations- Beta decay, the atomic number increases decreases( increases, decreases ) by 1 2 4( 1, 2, 4 ) and the mass atomic( mass, atomic ) number doesn’t change
Half life- the time it takes for the count rate or activity (number of decay per second) from a sample contains the isotope to fall to half its initial level.
Radiation cannot be ionising (form charge ions)
is exposing an object to nuclear radiation like which uses radiation.
Ionising radiation decreases the risk of cancer
Precautions when using ionising radiation include...
Shielding- gloves can protect against alpha radiation and beta and gamma radiation can be reduced a lead apron.
Monitoring
Exposure
Alpha radiation is strongly less weakly( strongly, less, weakly ) ionising. It can be stopped by dead skin cells and alpha emitters can be dangerous if inhaled or swallowed.
Beta radiation is less strongly weakly( less, strongly, weakly ) ionising. It can penetrate skin.
Gamma radiation is weakly less strongly( weakly, less, strongly ) ionising. Can penetrate the body but likely to pass through.
A tracer must...
Pass out of the body and be detected (gamma or beta)
Not be strongly ionising to minimise damage to body tissue (gamma)
Not decay into another radioactive isotope
Have a short half life so it is not present in the body for too long
Gamma rays through radiotherapy can pass into the body and destroy a tumour
