P4 - Atomic Structure

P4 - Atomic Structure

1. atom- the smallest part of matter

   • helium atom: 2 electrons/ 2 protrons/ 2 newtrons
     • protron: symbol- p / mass- 1 / charge- 1+ / location - nucleus
     • neutron: symbol- n / mass- 1 / charge- 0 / location- nucleus
     • electrons: symbol- e / mass- 1/1832 / charge- 1- / location- shell

2. half life:

   • even small amounts of materials have billions of billions of atoms
   • in an unstable isotope, those atoms may decay at any time- randomly
   • half life is a measure of time
     • - the time it takes for half of the isotope to decay / or for the count rate do decrease by half

3. nuclear equations:

   • the atomic number tells you the element
     • if the mass number is different to that found in the periodic table then it is an isotope