What is the Lewis structure of CH2O?

1. 1 Lewis Structure

Lewis structures are practised to assist in envisioning what a molecule looks like. It is a description of covalent bonding in which the shared electron pairs are exhibited as lines, and lone electron pairs are displayed as dots. When you draw a Lewis structure, it is essential to follow the octet rule to get the most stable electron configuration. (See What is the NH4 Lewis Structure?)

2. 2 Writing Lewis Structure

There are various things you need to keep in mind while formulating a Lewis structure. A few of them are:

• Always calculate the complete number of valence electrons in the molecule or ion. For anions, you need to add an electron for every negative charge and cations, subtract an electron for every positive charge.
• Put the least electronegative element in the centre of the molecule. Hydrogen atoms are always terminal atoms.
• Using a pair of electrons, create bonds between the central atom and very surrounding atom. For every single bond formed you need to subtract two electrons from the total number of valence electrons
• Put all the remaining electrons on the central atom. In case, if the octet rule is not met for the central atom, then you would have to move lone pairs of electrons to create multiple bonds to the central atom.
3. 3 What is the Lewis structure of formaldehyde, CH2O?

There are a total of 12 valence electrons:

Carbon -4 valence electrons
Oxygen= 6 valence electrons
Hydrogen= 1 valence electron

Carbon is the central atom:

O

|

H    -  C    -    H

Then the remaining 6 electrons are put around the O as lone pairs-

..

: O:

|

H     -   C   -    H

As C is less by one pair, hence a double bond is used.

:O:

||

H   -   C   -  H