How to determine and draw the Lewis structure of chemical compounds?

Question

C O

C H2 Cl2

Answer 1

start with carbon... carbon has 4 electrons in it's valence shell. carbon will almost always be the central element in your compound.

for the first one... oxygen has 6 valence electrons... a triple bond joins the 2 elements (therefore they share 6 electrons) and each element has one pair of unshared electrons... it looks like this
:C:::O:
notice that each atom has 8 electrons... and you can count the ones that carbon donated and the ones oxygen donated... maybe this will make it clearer
:C:;;O; imagine that each ; is a pair of electrons from oxygen

ok, the 2nd one is quite easy to explain, but difficult to draw on the computer... Carbon is the central atom, with 4 electrons. It shares one elctron with each of the 4 other elements. Hydrogen has 1 electron, and needs just one more to complete its shell (it is unique in this way; most need 8, but hydrogen just needs 2). Chlorine has 7 electrons in its outer shell and needs just one more to complete its outer shell.

So, the lewis structure is drawn in a cross fashion.

Horizontally... H:C:Cl:::

Vertically... H:C:Cl::: (where they cross at the C)

So, C has a pair of electrons on each side, and each Cl has a pair of electrons on each side (not 3 pairs on one side as I have drawn)

Check out the attached link for more help

Answer 2

For CO there is a triple bond between the atoms and a lone pair on both the C and O.

For CH2Cl2, carbon is the central atom. There is a single bond to each of the terminal atoms and three lone pairs on each Cl.

Do you have a procedure for doing Lewis structures? These two are pretty straight forward if you follow the procedure given in about any gen chem text.

Answer 3

A chemical formulation, which includes H2O (water) refers to a molecule. The factors of the expression (H and O consequently) refere to atoms of specific aspects. Hydrogen and Oxygen are 2 distinctive aspects that integrate in a 2 to a minimum of one ratio to make water.

Answer 4

Hi. C..O for the first. I think. : http://www.answers.com/main/ntquery?s=Lewis%20structure&gwp=16