Elements are compounds that cannot be broken down in any form or fashion. There are over one hundred substances that fallinto this classification. They cannot be interverted either. Molecules, however are combinations of chemicals. They have two or more atoms which makes them a whole different thing than an element is.
Elements are distinguished by an atomic number that denotes the protons that lie within the nuclei of its atoms. Molecules contain less energy that their parental atoms do and that is another way that elements and molecules are different. For those who study or research elements and molecules, they aren't very similar really once you know which is which. It is only easy to get them mixed up when you are not sure what either one of them are.