Covalent+Bonds

__Covalent Bonds:__

Covalent bonds are a type of chemical bond that form between different atoms. In a covalent bond, the atoms have to "share" electrons; this is due to little or no difference in the electronegativities of the atoms. Electronegativity is the ability of an atom to attract electrons from other atoms, and to determine the type of bond, one must subtract the electronegativities of the bonded atoms, and if the difference is less than 1.67 (z < 1.67), then the bond is covalent. They share electrons to fulfill the **octet rule,** which is to bond and share electrons so that their outermost energy level contains 8 valence electrons.

Here is an example I came up with: x = electronegativity of atom 1, y = electronegativity of atom 2, z = difference

x - y = z

If z < 1.67, the bond is covalent.

The reasoning for this is due to the fact that if electronegativity is an atom's ability to attract electrons, and the electronegativites of two or more bonded atoms are the same or similar, then either atom doesn't have the ability to take an electron from the other. Thus, due to having similar electronegativities that result in a difference lower than 1.67, the atoms bond through "sharing" rather than "exchanging" electrons. That is what makes a covalent bond, is a bond between atoms where the atoms must "share" electrons rather than "give away" or "exchange" electrons.

The strength of a covalent bond depends of the amount of electrons shared, and the **bond length.** A single bond is a covalent bonds in which two electrons are shared by both atoms, one from each, a double bond is two electrons from each atom, adding up to four, that are shared, and a triple bond is one where three electrons from each atom, resulting in six total, are shared by the atoms through bonding. A single bond is the weakest covalent bond, and as the bonds get greater in the number of electrons shared, the stronger they are. Bond length decreases with an increase in the electrons shared.

(Below, covalent bonding and single, double, and triple bonds are explained.)

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Covalent Compounds and types of Covalent Bonds:

There are two types of covalent bonds; they are nonpolar and polar. Nonpolar covalent bonds are atoms of the same element bonded to each other, such as three oxygen atoms bonded to each other to make ozone. Because all of the atoms are the same in origin and are from the same element, they all have the same electronegativities, thus the difference of the electronegativities is 0, and none of the atoms have the ability to take an electron from one another. Thuse, they have to share their valence electrons to fulfill the octet rule, thus forming a nonpolar covalent bond. Nonpolar covalent bonds are also known more commonly as molecules. Molecules are atoms of the same element bonded to each other. Ozone molecules are moleculesas they are three oxygen atoms bonded to each other. Nonpolar means "no poles", or no opposite charges as none of them can take electrons to become an electrically charged ion. Polar covalent bonds are bonds between atoms of different elements rather than the same element. There can be more than one atom of the same element bonded to an atom of another element. H20, for example, is a polar covalent bond because atoms of different elements are bonded to each other, as two hydrogen atoms are bonded to one oxygen atom. As ionic bonds gather and form into ionic compounds, so do covalent bonds. They come together to for molecular compounds, and their structure isn't a crystal lattice like that of ionic compounds, rather, they are "molecular" in structure. Their structure composes of molecules connected to each other. Water, for example, is a molecular compound, and it contains water molecules, which are H20, or two hydrogen atoms bonded to one oxygen atom. Carbon dioxide is another example. Carbon dioxide is composed of CO2 molecules, or one carbon atom bonded to two oxygen atoms.