Consider the elements of group 4a (the "carbon family"): c, si, ge, sn, and pb. what is the trend in metallic character as one goes down this group?

Generally, metallic character increases on going down the group and decreases on moving left to right.

Here, carbon is a non-metal, tin and lead are metals whereas silicon and germanium are metalloids.

On going down the group, carbon has the lowest metallic character as it readily accepts the electrons to complete the octet (less atomic radius, difficult to loose electrons) whereas lead has the highest metallic character as it is easy to loose electrons with increase in atomic radius.

Thus, metallic character increases from carbon to lead.

The final volume of the Oxygen O2 would simply be equivalent to the overall volume of the final mixture. This is because gases would occupy every space of its container. So in this case, the volume of CO2 and O2 would be the same and it would be 30 L. What would be different is the partial pressures of each.

 30 L