The first law of Mendeleev Md. Saifur Rahman Arranging the elements based on their molecular weight, their physical and chemical properties are noticed to periodically reoccur.You may likeDo I need car insurance?What is car insurance?How could I get cheaper car insurance?What is auto insurance?Why Adulterant food is the barrier to sound health?What are the producers?What are food preservatives?What is food chain?What is tertiary consumer?