P7 - Radioactivity Flashcards
John Daltons model?
Atoms were just solid spheres
JJ Thomson model?
Plum pudding model, atom is ball of charge with electrons scattered within it
Ernest Rutherford model?
Gold foil experiment, most atoms are empty space with ball of charge in the middle called the nucleus where all mass is
Niels Bohr model?
Electrons were in shells orbiting the nucleus
James Chadwick model?
He discovered neutrons in the nucleus
What is an isotope?
An element with same number of protons but different number of neutrons, same atomic number but different mass number
What is an alpha particle?
Made up of 2 protons and neutrons, stopped by skin and paper, highly ionising because of their size
What is alpha radiation?
Where an alpha particle is emitted from the nucleus of the radioactive nuclei
What is beta radiation?
Emitted by an atom where a neutron is divided into a proton and electrom
What is gamma?
A wave that is the most penetrating, stopped by thick lead and concrete
Define half life?
Time taken for amount of radioactive nuclei in an isotope to half
What is radioactive decay measured in?
Becquerels (Bq), 1 Bq is 1 decay per second
What is irradiation?
Occurs when materials are near a radioactive source, lead can block these radioactive substances
What is contamination?
When unwanted radioactive atoms get onto an object, possibly into the human body, protective clothing would help prevent this
What is gamma rays?
Where nucleus is getting rid of excess energy, no change to nucleus when radioactive source is emitting gamma radiation.
