Atomic structure and The periodic table

Atomic structure and The periodic table

1. ATOms

   • nucleus
     • contains protons and neutrons
       • Protons
         • +1 charge
         • relative mass of 1
         • the number of protons defines the element
         • protons = electrons
           • so atoms have no charge
           • if not it is an ion
             • Ions
               • ions are charged particles
                 • particles form ions when particles lose or gain electrons
               • metals lose electrons and form positive ions
                 • group 1 elements form 1+ ions
                 • group 2 elements form +2 ions
               • non-metals gain electrons and form negative ions
                 • group 7 elements form -1 ions
                 • group 6 elements form -2 ions
       • neutrons
         • 0 charge
         • relative mass of 1
     • its in the centre of the atoms
     • Radius of 1X10-14 m
     • it is positively charged cos of protons
   • electrons
     • mass very small
     • -1 charge
     • move around the nucleus in electron shells