Final answer:
The resulting substance when 1 carbon atom combines with 2 oxygen atoms is carbon dioxide, which is represented by the chemical formula CO2.
Step-by-step explanation:
When 1 carbon atom combines with 2 oxygen atoms, the resulting substance is called carbon dioxide. This molecule is represented by the chemical formula CO2. It is formed through a process that includes the sharing of two electron pairs between the carbon and each oxygen atom, forming two double covalent bonds. Carbon dioxide is a common gas found in the Earth's atmosphere and is produced by the combustion of carbon-containing compounds, such as when carbon reacts with oxygen during cellular respiration and when fossil fuels are burned.