Carbon monoxide (CO) burns readily in oxygen (O2), forming carbon Dioxide (CO2). Which of the follow equations is shows
this reaction and follows the law of conservation of mass?

the correct answer is a

i believe the answer is a.

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.