ELECTRON SHELLS

ELECTRON SHELLS

1. RULES

   • ELECTRONS ALWAYS OCCUPY SHELLS
   • THE LOWEST ENERGY LEVELS ARE ALWAYS FILLED FIRST THESE ARE THE ONES CLOSEST TO THE NUCLEUS
   • ONLY A CERTAIN NUMBER OF ELECTRONS ARE ALLOWED IN EACH SHELL
     • 1ST SHELL
       • 2
     • 2ND SHELL
       • 8
     • 3RD SHELL
       • 8
   • ATOMS ARE MUCH HAPPIER WHEN THEY HAVE A FULL ELECTRON SHELL LIKE THE NOBLE GASES IN GROUP 0
   • IN MOST ATOMS THE OUTER SHELL IS NOT FULL AND THIS MAKES THE ATOM WANT TO REACT

2. ELECTRON CONFIGURATIONS EXAMPLE

   • NITROGENHAS 7 PROTONS SO MUST HAVE 7 ELECTRONS
   • THE ELECTRON CONFIGURATION FOR NITROGEN MUST BE 2,5