Covalent Bond Examples
Covalent bonds are the most common and most important kind of bonding. It is a bonding between atoms within a molecule and forms the strongest bonds anywhere. Covalent bonds are chemical bonds between two non-metal atoms. A covalent bond between atoms is formed, when they share one or more pairs of electrons among each other. These shared pairs create a bond between the atoms, which binds them together into a singular unit, as a molecule. These shared electrons revolve in their outermost shells. A full outer shell needs eight electrons. The electrons in this outer shell are called valence electrons. The number of valence electrons is dependent on the size of the atom. Electrons then circle the atom in the same manner that planets orbit the stars. There is developed a path around the atomic nucleus. The first layer always contains only two electrons. The outer layers after that layer usually contain up to eight. For example, if an atom contained eight electrons, the first two would orbit very close to the atomic nucleus. The next six would orbit a little further away. Every atom wants a full outer shell. It desires to have eight electrons in the outer most shell. In this example the atom wants eight electrons in the outer shell but only has six. Therefore, the atom will borrow electrons from another atom. When this chemical bond takes place, a covalent bond is formed.
Covalent bonds can be split into two groups: Simple and Giant. Although they are both similar, there are some distinguishing factors. For example, Giant covalent bonds have relatively high melting and boiling points, whereas Simple covalent bonds have a relatively low melting and boiling point. This is because of the inter-molecular forces of attraction. With giant covalent bonds, the bonds between layers are very strong. However, with a simple covalent bond, the bonds between the atoms have a strong inter-molecular bond, but there are no bonds between the molecules, which is why it has a relatively low melting and boiling point.
When two atoms that are sharing electrons attract electrons with the same force, a non-polar covalent bond is formed. A non-polar covalent bond is a bond where the shared electrons are shared equally. On the other hand, a polar covalent bond is a covalent bond in which the shared electrons are more attracted to one of the atoms than the other. The shred electrons are more likely to be near the atom whose electronegativity is higher.
An example is water. Water consists of a covalent bond containing hydrogen and oxygen bonding together to make H2O. In this atomic molecule, two hydrogen atoms share their single electrons with the oxygen atom, which shares its own two electrons in return. This is an example of a covalent bond, which is created because of the higher electronegativity of oxygen.
A diamond is an example of Giant Covalent bond of carbon. A diamond has a giant molecular structure. Each carbon atom is covalently bonded to four other carbon atoms. Electrons are borrowed from these other carbon atoms. There is a tremendous amount of energy needed to separate the atoms in a diamond. This is because a covalent bond is strong and a diamond contains four covalent bonds. This makes the melting and boiling point if the diamond very high.
3. Vulcanized rubber
Another example is vulcanized rubber. Rubber is sticky when warm and brittle when cold. In 1939, Charles Goodyear accidently dropped a mixture of sulfur and natural rubber on a hot stove. The mixture heated up and became tough and elastic, forming vulcanized rubber. What happened? The covalent bonds transformed sulfur and natural rubber into the vulcanized rubber when it was heated. It changed because the covalent bonds between sulfur and rubber changed.
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