Scientific Tutor

How to do fill in valence electron dots for an Electron Dot Structure (Lewis structure) that is an ion?

Filling in valence electrons also for electron dot structures (Lewis structures) also requires us to take a look at special cases where how many valence electrons are in a covalent molecule might change. Those special cases are called ions. More specifically we will be working with polyatomic ions. These polyatomic ions will form an electron dot structure (Lewis Structure) but will have some valence electrons added to them or some taken away. This addition or subtraction of valence electrons is indicated by their charge. Where you add or subtract valence electrons while drawing an electron dot structure (Lewis Structure) in theory does not matter. However in practice, I have found that it is easier for people to understand if they subtract electrons from the central atoms or add electrons to the outer atoms.

Examples: Use the picture in the STARTING PICTURE COLUMN and then fill in the valence electrons as dots around the atoms they come from.  If needed you can look up how many valence electrons each element has with this valence electron periodic table. VIDEO Filling in Valence Electrons of an Ion Examples 1.

PRACTICE PROBLEMS: Use the picture in the STARTING PICTURE COLUMN and then fill in the valence electrons as dots around the atoms they come from. Try to remember how many valence electrons each element has from a regular periodic table. If needed you can look up how many valence electrons each element has use this valence electron periodic table.