Bonding
When elements combine with other elements to create a compound, a chemical bond is formed. This chemical bond is always formed via the electrons of an element. The electrons that can be used for bonding are usually in the outer orbital and are refered to as valence. There are two basic ways this electron may function to create a chemical bond.
The first way is through ionic bonding. In this type the electron will completely remove itself from its original atom and begin to oribit another atom exclusively. The bond between the two thus results because one atom has an extra negative charge while one atom has an extra positive charge. Just as in maginets and real life these opposite properties strongly attract each other.
The other type of bonding is called covalent bonding. In this instance the electron is shared by both atoms in an orbit which encompasses them both. Covelent bonds are more commonly seen in every day life, because it is the type most used in organic reactions. Covalent bonds can also be polar or nonpolar. Polarity tends to indacte how a certain compound may react to another compound.
One of the most important concepts of deciding how a compound will form is the octet rule. It states that most atoms want exactly 8 valence electrons in their outer shell. This means the will mostly tend to try to lose or gain electrons to become more like an electron configuration of a near by noble gas. Thus these elements, if the means to lose or gain electrons is present, will tend to exist in the corrisponding form:
All of these examples seek the electron configuration of Neon, because it is closest noble gas.
One must be sure to remember to make sure all electrons started initially in a problem can be accounted for at the end of the problem.
Predicting and identifing how bonds will form between atoms is one of the key elements in chemistry. Bonds are where potential energy is stored. Bonds also create stability to allow the formation of molucles.
A question arises when whe ask from where the energy comes when we perform a chemical reaction. This is one of the areas where people have the most trouble conceptualizing from where the potential energy comes. Most people that will tell you that both the process of forming bonds and of breaking bonds require energy to execute. Well, it logically can't work both ways because that would mean that every time a chemical reaction occurs (which by definition means the creation and/or formation of bonds) the universe would lose energy. The next guess is usually something about the bonds storing the energy, but in actuality it is the opposite which is what really happens.
It is often hard to visualize, but the formation of bonds gives off energy and the breaking of them absorbs energy. Thus when we refer to potential chemical energy we are refering to the potential that bonds will form, and then release energy. The phrases in the world which make us tend to think falsely are things like "breaking-down carbohydrates" to give ourselves energy. It is true that we do break the bonds of carbohydrates intially, and we lose energy in the process. But we more than make up for this lost energy by reforming the atoms into bonds which release energy ten-fold.
