**Aufbau Principle and filling of electrons in orbitals and sub shells**

Aufbau Principle for electronic configuration is not on the name of any scientist as usually happened in sciences. Aufbau means building up.

Electrons are build up in orbitals of different subshells of different energy levels on the basis of energy.

Electrons first fill lower energy level and then move to next higher level.

So electrons start filling from 1s orbital on wards in the following sequence:

**1s,2s,2p**** , 3s,3p,4s,3d,4p,5s,4d,5p,6s,4f,5d,6p,7s,5f,6d,7p,8s**

Simply it can be learned as **ssp sps dps dps fdps fdps**

Atomic Number | Element | Electronic Configuration |

1 | Hydrogen |
Is
^{1} |

2 | Helium |
Is
^{2} |

3 | Lithium |
1s
^{2} 2s^{1} |

4 | Beryllium |
1s
^{2} 2s^{2} |

5 | Boron |
1s
^{2} 2s^{2 }2p^{1} |

6 | Carbon |
1s
^{2} 2s^{2
}2p^{2} |

7 | Nitrogen |
1s
^{2} 2s^{2
}2p^{3} |

8 | Oxygen |
1s
^{2} 2s^{2
}2p^{4} |

9 | Fluorine |
1s
^{2} 2s^{2
}2p^{5} |

10 | Neon |
1s
^{2} 2s^{2
}2p^{6} |

11 | Sodium |
1s
^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2} |

12 | Magnesium |
1s
^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2} |

13 | Aluminium |
1s
^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2} |

14 | Silicon |
1s
^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2} |

15 | Phosphorus |
1s
^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2} |

16 | Sulphur |
1s
^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2} |

17 | Chlorine |
1s
^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2} |

18 | Argon |
1s
^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2} |

19 | Potassium |
1s
^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2} |

20 | Calcium |
1s
^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2} |

21 | Scandium |
1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}
3d^{1}^{} |

22 | Titanium |
1s
^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}
3d^{2} |

23 | Vanadium |
1s
^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}
3d^{3} |

24 | Chromium |
1s
^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}
3d^{5} |

25 | Manganese |
1s
^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}
3d^{5} |

26 | Iron |
1s
^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}
3d^{6} |

27 | Cobalt |
1s
^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}
3d^{7} |

28 | Nickel |
1s
^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}
3d^{8} |

29 | Copper |
1s
^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}
3d^{10} |

For More chemistry content visit https://www.chemswot.com