400
Carbon dioxide has two double covalent bonds. The total number of electrons shared between the single carbon atom and a single oxygen atom
What is four electrons?
The carbon atom shares 2 of its v electrons with one of the oxygen atom (which shares 2 of its v electrons).
The carbon atoms shares the other 2 v electrons it has with the second oxygen atom (which shares 2 of its v electrons). (a double bond means 2 shared pairs or 4 shared electrons. two double bonds means 2 sets of double bonds)
Bonus question:
How many total electrons are shared in this compound?