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Elements are substances that consist of ( only one, one or more, only two, two or more ) type of atom. Many everyday substances are elements, including ( nitrogen, ammonium, ammonia ), oxygen, ( iron, pyrite, steel ), gold, ( copper, chalcopyrite, copper chloride ) and aluminium. If two atoms have the same number of ( protons, protons and neutrons, neutrons ), they are of the same element.
Compounds are comprised of ( two or more, only one, more than one, only two ) different elements chemically ( bonded, attracted, combined ) in some way. There are three kinds of bonding, called ( covalent, ionic and metallic, covalent, stringent and additive, covalent, giant and ionic, constant, ionic and metallic, covalent, giant and molecular ). Examples of chemical compounds include carbon dioxide (( CO2, CO, C2O, C2O2 )), water (( H2O, H2O2, HO, HO2 )), ethane (( C2H6, C2H4, C6H2, C2H2 )) and sulphuric acid (( H2SO4, H2SO3, H2SO2, H2SO )).
The constituent parts in a mixture, unlike in a compound, are ( not chemically bonded, orbiting each other, magnetically attracted to each other ). These constituent parts also do not just have to be elements - they can also be compounds themselves. For example, air is a mixture of gases including carbon dioxide (CO2), oxygen (( O2, O, O3, OO )), nitrogen (( N2, N, NN, N3 )), argon (( Ar, Ar2, ArAr, Ar3 )) and water vapour (H2O). Another example is crude oil, a mixture of different ( fractions, gases, distillations ), which are themselves mixtures of various ( hydrocarbons, carbonates, hydroxides, carbohydrates ).