Electron Shells

Electron Shells

Electron shells are the levels around the nucleus where electrons can be found

• The atomic number is the same as the total number of electrons
• The period number is the same as the number of electron shells
• For main group elements- the group number is the same as the number of valence electrons 
• Each shell has a maximum number of electrons
• Vocab:
  • Valence shell- the outermost electron shell
  • Valence electrons- electrons located in the valence shell
  • Core electrons- all other electron besides the valence electrons
• Subshells: s, p, d, f
  • s- max # of electrons = 2
  • p- max # of electrons = 6
  • d- max # of electrons = 10
  • f- max # of electrons = 14

Direction of increasing n+l value :

1s

2s   2p

3s   3p   3d

4s   4p   4d   4f

5s   5p   5d   5f...

6s   6p   6d ... ... ...