Answer:
An atom always has the same number of electrons as protons. Electrons have an electric charge of -1 and protons have an electric charge of +1. Therefore, the charges of an atom's electrons and protons “cancel out.” This explains why atoms are neutral in electric charge.
Explanation:
The correct option is the second one, which is: Every million years.
The impact of a 1-kilometer object on our planet, would cause significant consequences. As the astronomers have found in other terrestrial bodies, this kind of impact creates largers craters on the surface.
It was thought that no one had studied further in the works of JJ Thomson and John Dalton at their time because there was no sufficient technology to conduct their works. However, their theory was eventually revised when Neils Bohr had theorised the modern atomic structure we know today.
