Dear Student,
Carbon di oxide is considered a compound because :
1. CO2 contains atoms of C and O2 which is the typical property of compounds.
2. In CO2 , C and O2 are chemically combined and can be seperated only through chemical reactions.
3. CO2 has its unique properties which match neither of its elements C and O2 .
Carbon is considered an element because :
1. Carbon is a ure chemical substance made of ony C atom.
2. Carbon cannot be broken down into smaller units of atoms.
3. Carbon possesses no bond formations unlike CO2 which contains bonds between C atoms and O2 atoms.
Regards