C1: Particles

C1: Particles

1. Atomic structure

   • Overall atoms are electrically neutral
   • Positively charged protons
     • Mass 1/12 of carbon 12
   • Neutrons
     • Mass 1/12 of carbon 12
   • Nucleus
   • Negatively charged electrons
     • Mass so small it barely affects the overal mass
   • Same number of electrons and protons
   • Atomic number (proton number)
   • Atomic mass

2. How atomic structure has changed over time

   • Democritus
     • Small indivisible spheres
   • Dalton
     • Indestuctible
   • Thompson
     • Positive mass with negatively charged electrons within
   • Rutherford
     • Positively charged, tiny, dense nucleus with electrons orbiting outside
   • Bohr
     • Positively charged nucleus made up of positively charged protons and neutrons with negatively charged electrons orbiting in 'shells'

3. Isotopes

   • An element which can have different atomic masses due to different numbers of neutrons
     • Hydrogen 1, 2, and 3
       • H 2 and 3 have neutrons H 1 doesn't
     • Carbon 12 and 14
       • C 14 has 2 more neutrons

4. How the periodic table is used to find the structure of atoms

   • Vertical=groups
     • Group=number of electrons on the outer shell
       • Group 0 have full outer shells
   • Horrazontal=periods
     • Period=number of occupied electron shells