Electron Configuration

• • Negative electrons orbit the nucleus of an atom in shells.
• Each shell holds certain number of electrons:

  • 1st - two electrons
  • 2nd - eight electrons
  • 3rd - eight electrons
• • Shells are filled from inside shell outwards - electrons can’t fill new shell until current one is full.
• Electron arrangement can show:

  • Group - number of electrons in outer shell.
  • Period - number of shells contains electrons.
  • Atomic number - total number of electrons in all shells.