# Solutions

1. | complete electronic configuration | abbreviated electronic config. | valence electrons |

a) Fe | 1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{6} | [Ar]4s^{2}3d^{6} | |

b) Er(aufbau) | 1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}5d^{1}4f^{11} | [Xe]6s^{2}5d^{1}4f^{11} | |

(mnemonic) | 1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{2}4f^{12} | [Xe]6s^{2}4f^{12} | |

c) Se | 1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{4} | [Ar]4s^{2}3d^{10}4p^{4} | |

d) Cs | 1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^{1} | [Xe]6s^{1} | |

e) Ag | 1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{1}4d^{10} | [Kr]5s^{1}4d^{10} | |

**2. Draw the complete energy level diagram for Mo and describe its magnetic properties.**

**3. Describe a possible set of quantum numbers for the 6th, 22nd, 44th and 80th electrons in mercury. **Using the Aufbau Principle

** 6th - **2,1,0,+1/2

**22nd **- 3,2,1,+1/2

**44th **- 4,2,2,-1/2

**80th** - 5,2,-2,-1/2

**4. Classify each of the following elements (based on their electronic configuration).**

As - Representative | Ru - Transition |

Cu - Transition | Cm - Inner Transition |

**5. Determine the electronic configuration and draw the expected orbital for each of the following sets of quantum numbers.**

3,1,-1,+½ - 3p^{3} | 5,0,0,-½ - 5s^{2} |

2,1,0,+½ - 2p^{2} | 4,2,-2,-½ - 4d^{10} |