radiation basics

• what are the three sub atomic constituents of an atom

  proton

  neutron

  electron
• where is most of the mass in the atom concentrated

  in the nucleus
• describe the arrangement of protons neutrons and electrons in an atom

  protons and netrons are found in the atoms nucleus , electrons are found in discrete energy levels (shells) around the nucleus~
• what type of charge does the nucleus of an atom have and why

  positive charge , the nucleus contains protons and neutrons , protons have a positive charge , neutrons have no charge therefore it is positive
• give 2 ways that en atoms electron arrangement can be changed

  absorbing electromagnetic radioation , emitting electromagnetic radiation
• how does an atom change when em radiation is absorbed

  electrons move to higher energy levels further away from the nucleus of the atom
• what happens to an atom when it emits em radiation

  electrons move to a lower energy level , they move towards the nucleus
• how does the ratio of electrons and protons result in an atom with no overall charge

  the number of protons is equal to the number of electrons , protons and electrons have equal and opposite charges , so the charges cancel
• what do all forms of the same element have in common

  they have the same number of protons
• what is the name given to the number of protons in an atom

  atomic number
• what is an atoms mass number

  the toal number of protons and neutrons in the atoms nucleus
• what is an isotope of an atom

  an atom of the same element which has the same number of protons but a different number of neutrons
• what property differs between an element and its isotope

  the mass of the atom
• how do atoms turn into positive ions

  they lose one or more of their outer electrons , electrons are negatively charged , so the resultant charge of the atom is positive
• what are the relative masses of a proton neutron and electron

  proton 1 , neutron 1 , electron negligible
• what are 4 types of nuclear radiation

  alpha particles , beta particles , gamma rays , neutrons
• what is meant by background radiation

  radiation that is always present , it is im very small amounts and not harmful
• give 4 sources of background radiation

  rocks , cosmic rays from space , nuclear weapons testing , nuclear accidents