The compound and the number of atoms of each element

  e formula for a compound indicates the elements that make up the compound and the number of atoms of each element present in the compound. The numbers of atoms are indicated by the use of small numbers called subscripts. Sometimes groups of atoms act as a single atom. Such a group of atoms is called a polyatomic ion. If a polyatomic ion is used in a formula more than once, it is put in parentheses and the subscript appears outside of the parentheses. When a subscript appears outside the parentheses, it indicates that all the elements inside the parentheses should be multiplied by that subscript. For example, the formula Fe(OH)3 indicates the combination of 1 atom of iron (Fe), 3 atoms of oxygen (O) and 3 atoms of hydrogen (H). Name Use Formula Atoms in Formula Calcium Carbonate Limestone CaCO3 Ca= calcium 1 C = carbon 1 O = oxygen 3 Aspirin Pain reliever C9H8O4 Magnesium Hydroxide Found in milk of magnesia Mg(OH)2 Paradichlorobenzene Moth crystals C6H4Cl2 Acetic acid Found in vinegar C2H4O2 Trinitrotoluene (TNT) Explosive C7H5(NO2)3 Calcium dihydrogen Phosphate Fertilizer Ca(H2PO4)2 Name Use Formula Atoms in formula Pyrite Fool’s gold FeS2 Sucrose Sugar C12H22O11 Pentane A component in gasoline C5H12 Sulfuric Acid Used in car batteries H2SO4 Cellulose Found in wood products like paper /pencil C6H7O2(OH)3 Asbestos Insulator H4Mg3Si2O9 Dichlorodiphenyl-trichloroethane (DDT) Banned pesticide C14H9Cl5 Silicon dioxide Sand SiO2 Iron oxide Rust Fe2O3 Butane Lighter fluid C4H10