C) chemical change, because burning gives new substances, but does not change nuclei of elements
Answer:
₈₄Po²²⁰
Explanation:
₈₆Rn²²⁴ → ₈₄Po²²⁰ + ₂He⁴
In given decay reaction alpha particle is emitted from Radon.
Alpha radiations:
Alpha radiations are emitted as a result of radioactive decay. The atom emit the alpha particles consist of two proton and two neutrons. Which is also called helium nuclei. When atom undergoes the alpha emission the original atom convert into the atom having mass number 4 less than and atomic number 2 less than the starting atom.
Alpha radiations can travel in a short distance.
These radiations can not penetrate into the skin or clothes.
These radiations can be harmful for the human if these are inhaled.
These radiations can be stopped by a piece of paper.
Answer:
solid substance formed during liquid solution, is known as precipitate. For example: in the reaction of silver nitrate and sodium chloride, a precipitate of silver chloride is formed which is white in colour. Precipitation can be of any colour like white, yellow, black.