scandium is a transition metal and shows a valency of 3.
Answer:
Lavoisier made an important contribution to chemistry by the law of conservation of mass
Explanation:
The law of conservation of mass tell us, that the mass doens't change in a system. You have the same mass at the begining and in the end of a reaction.
Matter is neither created, nor destroyed in a chemical reaction.
This law also states that mass of reactants is the same of products in any chemical reaction
Alpha particles are helium nucleus ! so answer is A !
it is made by ionization of helium, when both the electrons are out , then two unit of positive charge is one helium and thus called alpha particle !
