Formal Charge
In terms of Lewis structures, formal charge is used in the description, comparison and assessment of likely topological and resonance structures by determining the apparent electronic charge of each atom within, based upon its electron dot structure assuming exclusive covalency or non-polar bonding. It has uses in determining possible electron re-configuration when referring to reaction mechanisms, and often results in the same sign as the partial charge of the atom, with exceptions. In general, the formal charge of an atom can be calculated using the following formula, assuming non-standard definitions for the markup used:
where:
- is the formal charge.
- represents the number of valence electrons in a free atom of the element.
- represents the number of unshared electrons on the atom.
- represents the total number of bonds the atom has with another.
The formal charge of an atom is computed as the difference between the number of valence electrons that a neutral atom would have and the number of electrons that belong to it in the Lewis structure. Electrons in covalent bonds are split equally between the atoms involved in the bond. The total of the formal charges on an ion should be equal to the charge on the ion, and the total of the formal charges on a neutral molecule should be equal to zero..
Read more about this topic: Lewis Structure
Famous quotes containing the words formal and/or charge:
“This is no argument against teaching manners to the young. On the contrary, it is a fine old tradition that ought to be resurrected from its current mothballs and put to work...In fact, children are much more comfortable when they know the guide rules for handling the social amenities. It’s no more fun for a child to be introduced to a strange adult and have no idea what to say or do than it is for a grownup to go to a formal dinner and have no idea what fork to use.”
—Leontine Young (20th century)
“Well done, good and trustworthy slave; you have been trustworthy in a few things, I will put you in charge of many things; enter into the joy of your master.”
—Bible: New Testament, Matthew 25:21.