Wednesday, February 23

Today in class the first thing that we did was get our lab notebooks back. Once we got those back Mr. Henderson gave us our lab grades and grade sheet with our latest test on it, but he noted that some of the homework has not been recorded. After that he told us that the next unit that we would be studying is chemical bonding. In this lesson we will be learning how to understand the nature of a chemical bond, about the various categories of bonds, what causes 2 atoms to bond together and much more. Mr. Henderson started off by telling us that some people like to think of a bond as a stick that holds things together. He then reassured us that this is not really how it is. The bond is moving to try and find balance, so that a happy state is found between the protons and electrons. It was also made very clear that protons are attracted to electrons. Mr. Henderson also did a little demonstration with 2 magnets(oppositely charges) that he had attached to a track. He noted that if pushed together they repel each other. Then he took out a spring and attached it to the magnets so that they where almost touching. He showed us that the magnets where in a happy state and if pushed too close together they repelled each other and if forced together from a far distance they would do the same. After the demonstration he had us look inside our new unit 9 packets. We first looked at the diagram and saw that as the potential energy decreases and the distance between the nucleus decreases the protons and electrons are brought to a happier state. We then went over ionic and covalent bonds. Ionic bonds are formed with ions; usually occur between metals and non-metals; formed by ions that have opposite charges. There are two types of covalent bond; polar and nonpolar. In polar covalent bond the electrons are shared unequally and in nonpolar the electrons are shared equally. Covalent bonds occur between two non-metals. On page 2 we talked electronegativity, and how the greater the difference in electronegativity , the greater the ionic character of the bond. We then matched bonds between C-H, C-C, C-N, C-O and C-F and how they are portrayed in the pictures. After that looked at a chart and filled bonds. We filled in the information that was needed to find if the bond was nonpolar covalent, polar covalent or ionic. If the difference in electronegativity is > 1.7 then the bond is ionic, < 0.4 it is nonpolar covalent and greater than or equal to 0.4 and less than or equal to 1.7 then it is polar covalent. For our homework we had to do pages 1-3 in the unit 9 packet.