Detailed Electronic Configurations of Ions Optional

To get the electronic configuration of ions, a new rule is followed. First we write the electron configuration of the neutral atom (Chap. 4). Then, for positive ions, we remove the electrons in the subshell with highest principal quantum number first. Note that these electrons might not have been added last, because of the + / rule. Nevertheless, the electrons from the shell with highest principal quantum number are removed first. For negative ions, we add electrons to the shell of highest principal quantum number. (That shell has the electrons added last by the n + / rule.) 

Being able to write correct electronic configurations for transition metal ions becomes very important in discussions of coordination compounds (in the second semester of general chemistry). 

Which seven elements form diatomic molecules when they are uncombined with other elements  

How many atoms of each element are there in a formula unit of each of the following substances  

Which elements acquire the electronic configuration of helium by covalent bonding  

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