<p>Hey, could some one please help me with these. Thanks.</p>
<p>Draw a Lewis Dot structures for the ionic compounds:</p>
<li><p>KF</p></li>
<li><p>CaBr2</p></li>
</ol>
<p>Draw a Lewis Dot structures for the covalent compounds:</p>
<li><p>OF2</p></li>
<li><p>PCl3</p></li>
<li><p>CH4</p></li>
<li><p>H2</p></li>
</ol>
<p>Thank you very much.</p>
<p>When doing Lewis Dot Structures, you first have to count the amount of valance electrons in the compound.</p>
<p>So say you have KF, whic has 8 valence electrons. You always start by bonding them with a single line which represents two electrons. So if you just used 2 electrons, you have 6 left and all of those are just put on the Flourine, with 2 dots on each side.</p>
<p>So now you have something like OF2, that has a total of 20 valence electrons. You know that Flourine is more electronegative, so it will get the electrons first, with the Oxygen in the middle of the Flourines, so it looks like F-O-F. So you put 6 electrons on each Flourine, and you used 4 already to bond them to the Oxygen, thats a total of 16 that were used so far, u can use the 4 left over to put them on the Oxygen, giving each ion a total of 8 electrons.</p>
<p>So, with something like PCL3, u have 26 valence electrons. 6 are used for bonding, 18 are put on the Chlorines, so you can put the extra 2 on P for 8 on each.</p>
<p>Just remember the key is to get 8 electrons on each element. If there are too few electrons, then u have to make double or triple bonds.</p>
<p><a href="http://www.chemistrycoach.com/lewisflow.htm%5B/url%5D">http://www.chemistrycoach.com/lewisflow.htm</a></p>
<p>Thank you. But I dont quit understand the PCl3 one. But for the CH4, I got H-H-C-H-H. Then for H2, I got H-H. Are these right? Thank you.</p>
<p>Anyone?????</p>
<p>chlorine bonding? is that what you are asking about?</p>
<p>No, I dont think so. Just doing the lewis dot structures for each compound.</p>
<p>No, its not H-H-C-H-H.</p>
<p>It has to be tetrahydral, with an H on each side, so it looks like a diamond. CH4 is nonpolar, and it is seen by its symmetry, it has 8 valence electrons and when there is a C-H bond, 2 electons are used; Hydrogen has a full shell of 2 and Carbon has a full shell of 8.</p>
<p>Make sure you know your VESPR rules with shapes and angles.
About the PCL3, the goal of any bonding is to get 8 electrons for the more electronegative ion. Always count the valence electrons in total and evenly distribute them on the outside ions. Thats all I can tell you.</p>
<p>Just a few rules
1) If there are too many electrons after each ion has 8, you put them on the central ion.
2) If there are too few electrons for the central, then you have to make a double bond with one of the elements. An example would be BCl3, there are 24 valence electrons and 6 are used in bonding, 18 are put on the outside to give 6 more to each Chlorine, so the Boron has only 6 electrons. Make a double bond between one of the Chlorines to the Boron and then every element is happy :-)</p>
<p>H2 is just H-H</p>