Chemistry Review  Element  Consists of entirely one type of atom  Many found in the body  Oxygen65%  Carbon18.6%  Hydrogen9.7%  Nitrogen3.2%  Calcium1.8%  Phosphorus1%  Potassium<1%  Chlorine, Magnesium, Sodium, Sulfur, Iron, Iodine  Compound  Molecules containing more than one type of atom  Water - H 2 O  Salt - NaCl  Methane - CH 4