Flashcards in Radioactive materials Deck (84)
What is the smallest part of an element?
What forms the nucleus of an atom?
Neutrons and protons
What is the smallest particle in the atom?
What is the charge of an electron?
What is the relative mass of a proton?
1 (Also about 2000 times the mass of an electron)
What is the relative mass of a neutron?
What is the charge on a neutron?
What is the charge of an atom?
What does an atom have that makes it neutral overall?
Equal numbers of protons and electrons.
How was evidence on the structure of an atom obtained, by Rutherford and others?
They scattered alpha particles using gold foil.
What was the result of the Rutherford-Geiger-Marsden alpha scattering experiment?
Most alpha particles went straight through; a few were deflected at small angles; even fewer bounced back.
What was deduced about the structure of the atom using the results of the Rutherford-Geiger-Marsden alpha scattering experiment?
The atom must be mostly empty space as most particles went straight through; the mass and charge of the atom is concentrated in a small area (the nucleus); the nucleus is positive as the positive alpha particles were repelled
What hold protons and neutrons together?
The strong nuclear force.
What does the strong nuclear force have to balance?
The electrostatic repulsion between protons.
What determines which element an atom is, and therefore the chemical properties?
The number of protons.
What are isotopes?
Atoms of the same element with the same number of protons but different numbers of neutrons. For instance, hydrogen can have 0, 1 or 2 neutrons, to give hydrogen, deuterium and tritium. Most isotopes don't have different names, you just use the atomic mass!
What is the name for an atom that is unstable?
It is radioactive.
What happens when a radioactive element emits ionising radiation?
It becomes more stable.
What is the low level ionising radiation that is all around us?
Where does background ionising radiation come from?
Some from space, most from rocks and soil.
How can you tell when an individual atom will decay?
You can't, it is random
What determines the amount of energy emitted by a radioactive element?
Only the amount of the element, it is unaffected by anything else.
What are the types of ionising radiation (including particle radiation)?
Alpha, beta, gamma
What is the charge on an alpha particle?
What is the charge on a beta particle?
What is the charge on gamma radiation?
What is the relative mass of an alpha particle?
4 (2 protons + 2 neutrons)
What is the relative mass of a beta particle?
What is the relative mass of gamma rays?