Atomic Structure Flashcards
What is an Isotope
an atom of the same element with a different number of neutrons
What is the mass number
Total number of protons and neutrons
What is the atomic number
Total number of protons in the nucleus
Describe the plum pudding model
a ball of positive charge with electrons embedded in it
Explain the Rutherford and Marsden alpha scattering experiment
They bombarded thin gold foil with alpha particles and said if the Plum Pudding model was correct the positively charged alpha particles would pass through
Some were reflected so they must of been repelled by the same charge alpha particles carried, and the charge must of been heavier
They concluded the mass of the atom was concentrated in a central nucleus which was positive surrounded by negative electrons
Why do atomic nuclei give out radiation
- Activity
- Count rate
- they give out radiation to become more stable
- activity is the rate at which a radioactive source decays
- count rate is the number of decays per second
what does it mean if a wave is ionising
It knocks electrons off of atoms
What is the most ionising, least penetrable type of radiation
Alpha
Components of an alpha wave and its hazards
two neutrons an two protons ejected form the nucleus
highly likely to be absorbed can cause damage if passing through living cells
Components of beta radiation and hazards
A high speed-electron ejected from the nucleus as a neutron turning into a proton. The proton stays in the nucleus
Likely to cause damage if absorbed by living cells
Can penetrate the body to inner organs
gamma components and hazards
Electromagnetic radiation emitted from the nucleus
Likely to pass through living cells without being absorbed and causing any harmful radiation
What is radioactive contamination
the unwanted presence of materials containing radioactive atoms on other materials
What is Irradiation
exposing and object to radiation but doesn’t cause it to become radioactive
How can unwanted irradiation be protected agains
- using sources of the lowest activity for the shortest amount of time
- wearing appropriate clothing such as a lead apron and not using your bare hands
Why would food contaminated with an alpha source be the most harmful
because it is the most strongly ionising
