2.3 Electron Arrangement and Valence Electrons:

  • electron arrangement:

    • describe the arrangement of electrons in the atom

ENERGY LEVELS AND THE ARRANGEMENT OF ELECTRONS:

  • Energy levels: atoms can have only certain allowed energies

  • Electrons in the lowest energy levels: closest to the nucleus

  • inert: undergoing a few chemical reactions

  • Noble gases: no partially filled energy levels; they are stable arrangement of electrons

VALENCE ELECTRONS AND PERIODICITY:

  • valence electrons: highest energy level of an atom

  • physical and chemical properties of an element.