Biology Forums - Study Force

Hi!

I've been practicing Lewis Diagrams and I'm a bit stumped on something...my drawing for CO2 shows that both Oxygen atoms on both sides of the Carbon central atom have 2 lone pairs each for a total of 4 lone pairs of electrons. Why are certain websites telling me there are no lone pairs for CO2 even though I've satisfied the octet rule buy utilising double bonds?? Or does it not matter unless the CENTRAL atom is filled?

Please refer to the attachment (sorry for the horrible drawing :P)

I think that, as you said, CO2 has 4 lone pairs (two for each O).
Can you post the websites where you found that CO2 hasn't got any lone pair?

Certainly!

www.elmhurst.edu/~chm/vchembook/208introgeom.html (http://www.elmhurst.edu/~chm/vchembook/208introgeom.html)

butane.chem.uiuc.edu/pshapley/genchem2/B3/1.html

chemwiki.ucdavis.edu/Wikitexts/UCD.../Geometry_of_Molecules

I think that these websites are referred to the center atom (carbon) of CO2.

(From the websites: Using the VSEPR theory, the electron bond pairs and lone pairs on the center atom will help us predict the shape of a molecule.
From the Lewis structure we can see that the carbon in CO2 must make 2 sigma bonds and it has no lone pairs.)

So, when it says that CO2 has no lone pairs, it means that carbon does not have lone pairs.
Each oxygen surely has two lone pairs of electrons.

Oh ok so it really just depends on the central atom then (in terms of the shapes I assume)? It just confused me because I was sure I had it right...

I think so. But I am not familiar with VSEPR theory and angles of atoms in a molecule.

It goes by the central atom, C, and by the formal charge on each atom.

So for CO2,it should be a Carbon in the middle and Two Oxygens on opposite sides of it with 4 Lone electrons surrounding each oxygen. the carbon should be bonded to each oxygen with double bonds