ORBITAL NOTATION FILLING ORDER memorize N1 N2 N3

ORBITAL NOTATION FILLING ORDER – memorize! N=1 N=2 N=3 1 s_ 2 p_ _ _ 3 s_ 3 p_ _ _3 d _ _ _ ORBITALS- PLACE WHERE ELECTRONS MOST LIKELY FOUND. Holds 2 electrons (pair) maximum. SUBLEVELS- subdivision of a shell. s: holds 2 electrons, (one orbitals)-found in all shells p: holds 6 electrons, (three orbitals)-second shell and up d: holds 10 electrons, (five orbitals)-third shell and up

AFBAU PROCESS: WHEN DIAGRAMMING AN ELECTRON CONFIGURATION, ELECTRONS ARE PLACED FROM THE INNERMOST(LOW ENERGY) TO THE OUTERMOST(HIGH ENERGY) ORBITALS IN ORDER. ONLY THE OUTERMOST ORBITAL AND SUBLEVEL MAY BE UNFILLED (EXCEPT FOR SOME TRANSITION METALS). HUNDS RULE: WHEN FILLING A p, d, OR f SUBLEVEL YOU MUST ADD ONE ELECTRON FIRST AND THEN GO BACK AND PAIR THEM UNTIL ALL ELECTRONS ARE SHOWN. p___ PAULI EXCLUSION PRINCIPLE: ELECTRONS IN AN ORBITAL MUST HAVE OPPOSITE SPIN NOTATION, ONE HAS AN UP ARROW , ANT THE OTHER A DOWN ARROW,

FILLING ORDER 1 s_ 2 p_ _ _ 3 s_ 3 p_ _ _ 3 d _ _ _ EX) Show the electron configuration of 2 8 Na 11 2 -8 -1 1 1 s_ 2 p_ _ _ 3 s_ 3 p_ _ _ 3 d _ _ _ FIRST SHOW 2 ARROWS(ELECTR ONS) IN THE FIRST SHELL After the first shell has 2 electrons, place 8 electrons in shell n=2 as indicated on the periodic table ground state THE PERIODIC TABLE INDICATES ONLY ONE ELECTRON (ARROW) IN THE THIRD SHELL. THIS IS THE VALENCE, AND YOU ARE NOW DONE!