can you help me with the first two - I have a chart of 20.
Substance O - check any appropriate
element - compound - symbol-formula - atom - molecule
Substance O2 - check any appropriate element - compund - symbol-formula- atom - molecule
Substance O - check any appropriate
element - compound - symbol-formula - atom - molecule
Substance O2 - check any appropriate element - compund - symbol-formula- atom - molecule