Covalent+Bonds

media type="custom" key="6201893" Table of Contents **
 * Sorry about the gigantic text above, we cant get it off!
 * 1. **** What are Covalent Bonds? ****​**
 * 2. **** Why do Atoms Bond? **
 * 3. ** ** How Covalent Bonds Form **
 * 4. ** ** Electron Sharing **
 * 5. ** ** How Many Bonds? **
 * 6. ** ** Double and Triple Bonds **
 * 7. ** ** Molecular Compounds **
 * 8. ** ** Low Melting and Boiling Points **
 * 9. ** ** Poor Conductivity **
 * 10. ** ** Unequal Sharing of Electrons **
 * 11. ** ** Polar and Nonpolar Bonds **
 * 12. **** Polar Bonds in Molecules **
 * 13. **** Attractions Between Molecules **
 * 14. **** Works Cited **

Covalent bonding is "a bond formed when two atoms share electrons" (Frank, Little, and Miller 31.) This is the type of bond that holds together the atoms of a water molecule H2O, and carbon dioxide CO2.
 * What are Covalent Bonds? **​

Here is a video on covalent bonding (start at 0:53) media type="custom" key="6201737" teachertube.com (Bonding Animation)

** Why do Atoms Bond? ** Atoms bond to make more stable molecules. These molecules consist of two or more different elements in different quantities. An element will bond with other elements in a way that both elements have an outside shell of usually eight valence electrons. However, when getting into more complex elements past the 18th element, the bond will cause that element or elements to have an outside shell of 18 or 32 valence electrons. However, in the case with hydrogen and helium, there are only two.

This oxygen molecule will bond to become more stable which requires a full outer shell of eight electrons; like this neon atom has.

How Covalent Bonds Form Think about working on a big project with a friend. To get it done, you need to both pull the same amount of weight to get a good grade. This concept is the basic concept of covalent bonding. Both of the elements share electrons with each other to become more stable. This usually only occurs between atoms of nonmetals. On the other side of the coin, ionic bonding usually occurs between atoms of nonmetals and metals. However, some more complex substances are created using both covalent and ionic bonds (Hawkin, Joy. __The Story of science Einstein__ 187).

Electron Sharing Almost all nonmetal’s atoms can combine with other nonmetal’s atoms by means of sharing electrons with each other. A scientist by the name of Edward Franklin said, “The combining power of the attracting elements… is always satisfied by the same number of atoms.” This means that any atom of a given element will bond the same amount of times as each other (Hawkin, Joy. __The Story of science Newton__ 295). The only elements that can’t do this very easily are the noble gases because they have a full shell of eight valence electrons. In some cases two atoms of the same element can combine like O2. media type="custom" key="6208751" How Many Bonds? The amount of bonds an element’s atom can have is very easy to figure. All you have to do is count the amount of valence electrons the element’s atoms have and add up to eight. The number needed to get to eight is the amount of bonds it can have. For example, a Fluorine atom has seven valence electrons. The number needed to go from seven to eight is one; therefore a fluorine atom can form one bond.

Double and Triple Bonds Some atoms can bond more than one time. This is the case with any nonmetallic element that is not in the 17th group. Even though they are different, they are very much the same. All the rules on how to find the amount of bonds stick and so do the basic rules of bonding.

Molecular Compounds “A molecular compound is a compound that is composed of molecules.” (Frank, Little, and Miller 32). Compared to ionic compounds, they have generally lower melting and boiling points. Also, when dissolved in water, they don’t conduct electricity.

The reason that molecular compounds have lower melting and boiling points than ionic compounds is very simple. It's because the bonds in molecular compounds are much weaker than the bonds in ionic compounds. This means that less temperature is needed to break the bond and create a liquid or gas. This is why many nonmetals are gases art room temperature.
 * Low Melting and Boiling Points **

Poor Conductivity
 * Most molecular compounds don’t conduct electricity. This is because the particles aren’t charged and therefore nothing moves causing electricity not to flow. Materials like plastic or rubber are used to insulate electrical wires because they are made of molecular substances. **


 * Unequal Sharing of Electrons **
 * Have you ever fought over something and both people were pulling on it? You know that if you both pull with the same amount of force, it will not move. However, if one of you pulls harder, it will start moving away from the lesser force towards the stronger force. The same happens with covalent bonds. “Atoms of some elements pull more strongly on shared electrons than do atoms of other elements.” (Frank, Little, and Miller 33). This causes the electrons to move towards one atom causing the bonded atoms to have a slight electrical charge. Even though they are charged, they are not charged as strong as ionic bonds. **


 * Polar and Nonpolar Bonds **
 * An unequal sharing of electrons will cause the two atoms involved to gain slight electrical charges. The atom with the stronger pull will have a negative charge and the one with the weaker pull will have a positive charge. A covalent bond were electrons are shared unequally is called a polar bond. If the two atoms share the electrons equally, the atoms have no charge and form a nonpolar bond. **


 * Polar Bonds in Molecules **
 * It makes complete sense that a molecule with all nonpolar bonds would overall be nonpolar; but molecules made with polar bonds can also end up nonpolar themselves. A good example of this is a carbon dioxide molecule. In this molecule, the two negative forces of the oxygen atom’s pull cancel each other out, creating a nonpolar molecule. However, the exact opposite can happen as well. In a water molecule, the two hydrogen atoms are being pulled in the same direction, causing the molecule to have a charge. **

This carbon dioxide molecule has no charge because the negative charges move apart and cancel each other out; with this water molecule the negative charges are moving in the same direction causing the molecule itself to have a negative charge.

If you could go from the size of a human to the size of a molecule, you would see something very interesting. The negatively charged oxygen atoms attract the positively charged hydrogen atoms, pulling the water molecules closer together. However, in molecules like carbon dioxide where they aren’t charged, they do not attract each other. The properties, like state of matter, differ between substances because of their molecular make-ups, which determine if the molecule is polar or nonpolar. This is shown in the form of density as well. When you pour water and oil into a cup, the water stays with water and the oil stays with oil because the molecules are attracted to each other with different forces.
 * Attractions Between Molecules **

**Works Cited**

"h2o molecule." //therideinside //. Web. 11 May 2010. []. (h2o molecule pic. at top of page)

Frank, David, Little, John, and Miller, Steve. //Chemical Interactions //. Upper Saddle River, NJ: Pearson, 2009. 30-35. Print. (Science book used for info and subtitles) <span style="font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%;">

"Covalent Bonding Graffiti Text." //<span style="font-family: 'Arial','sans-serif';">easygraffititext //. Web. 12 May 2010. [] <span style="color: #000000; font-family: 'Arial','sans-serif'; font-size: 10pt; line-height: 115%;">. (Graffiti text at top of page)

Hawkim, Joy. __The Story of Science Newton at the Center__. New York: Smithsonian Books, 2005

Hawkim, Joy. __The Story of Science Einstein Adds a New Dimension__. New York: Smithsonian Books, 2007

"oxygen atom." //library.thnkquest.org//. Web. 20 May 2010. []. (oxygen atom pic.)

"neon atom." //library.thinkquest.org//. Web. 20 May 2010. []. (neon atom pic.)

"Covalent Bnding." //toondoo//. Web. 20 May 2010. <toondoo.com>. (comic strip)

"carbon dioxide molecule." //library.thinkquest.org//. Web. 21 May 2010. [%20(carbon|http://library.thinkquest.org/11226/image/co2.jpg.] (carbon dioxide molecule pic.)

"H2O molecule." //dichotomistic//. Web. 21 May 2010. [] (H2O molecule)

"Bonding Animation." //teachertube//. Web. 22 May 2010. []. (covalent bonding vid.)

"single, double, and triple bond." //astro.lsa.umich.edu//. Web. 22 May 2010. []. (single double and triple bond pic.)