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How many types of atom does carbon dioxide have?
Aluminium (Al), water (H2O), oxygen (O2) and carbon dioxide (CO2) are substances. Some substances are elements and some substances are compounds. Elements have only one type of atom whereas compounds have more than one type.
Aluminium is an element: it has only one type of atom (i.e. it has only aluminium atoms). Oxygen has only one type of atom, so it is also an element.
Carbon dioxide has two types of atom (carbon and oxygen), so it is a compound. Sulphuric acid (H2SO4) is also a compound: it has three types of atom (hydrogen, sulphur and oxygen). Water is also a compound.