Question 4.9: Drawing an Electron-Dot Structure for CH2O Draw an electron-......
Drawing an Electron-Dot Structure for CH_2O
Draw an electron-dot structure for formaldehyde, CH_2O, a compound used in manufacturing the adhesives for making plywood and particle board.
STRATEGY
First, count the total number of valence electrons. Carbon has 4, each hydrogen has 1, and the oxygen has 6, for a total of 12. Next, decide on the probable connections between atoms, and draw a line to indicate each bond. In the case of formaldehyde, the less electronegative atom (carbon) is the central atom, and both hydrogens and the oxygen are bonded to carbon:
H-\overset{\underset{|}{O}}{C} \ – \ HSix of the 12 valence electrons are used for bonds, leaving 6 for assignment to the terminal oxygen atom.
H-\overset{\underset{|}{:\overset{..}{O}:}}{C} \ – \ H\\\qquad \ \ \nwarrow \text{Only 6 electrons around carbon}At this point, all the valence electrons are assigned, but the central carbon atom still does not have an octet. We therefore move two of the oxygen electrons from a lone pair into a bonding pair (Step 5), generating a carbon–oxygen double bond and satisfying the octet rule for both oxygen and carbon.
Formaldehyde, CH_2O
