Question

owing is the correct Lewis dot (electron dot) structure for carbon dioxide?
Carbon has four valence electrons, and oxygen has six valence electrons. If carbon and oxygen bond covalently, which of the following is the correct Lewis dot (electron dot) structure for carbon dioxide?
A Lewis dot structure with the following configuration: one oxygen atom with four valence electrons, a double bond to a carbon atom, followed by a double bond to a second oxygen atom which has four valence electrons.
A Lewis dot structure with the following configuration: one oxygen atom with four valence electrons, a single bond to a carbon atom with four valence electrons, followed by a single bond to a second oxygen atom which has four valence electrons.
A Lewis dot structure with the following configuration: one oxygen atom with six valence electrons, a single bond to a carbon atom, followed by a single bond to a second oxygen atom which has six valence electrons.

Answer 1

According to data the structures are as drawn below. 
Lewis structure is drawn by adding valence electrons of all elements present in a given compound.
In this case,
6 + 6 + 4 = 16 valence electron
secondly, the central atom is drawn in center and other outside, like carbon in center.
Then single bonds are drawn to connect the central atom to side atoms and 2 electrons for each single bonds are subtracted from total electrons, in this case 16-4=12, these 12 electrons are added to the most electronegative atoms, in this case to oxygen atoms. After that changes are made in a uch a way that each atom gets a complete octet number (8 electrons). 
So, Among these three  structures only the Blue structure is correct because in it each atom has a complete octet. While in other two oxygen or carbon has deficiency of electrons.