Answer:
Law of conservation of mass
Ernest Rutherford
Explanation:
The basic law of behavior of matter that states that "mass is neither created nor destroyed in a chemical reaction or physical change".
This is the law of conservation of mass. It is very essential in understanding most chemical reaction. Also, in quantitative analysis, this law is pivotal.
Ernest Rutherford was the scientist that stated that the nucleus is made up of positive charge. It was not until James Chadwick in 1932 discovered the neutron that we had an understanding of this nuclear component.
Rutherford surmised from his experiment that because most the alpha particles passed through the thin Gold foil and just a tiny fraction was deflected back, the atom is made is made up of small nucleus that is positively charged.
