The isotope formed during radioactive decay

There are main groups in the modern periodic table of elements

Calculate the mass of silver needed to react with chlorine to produce 126g if silver chloride?

Which of the following observations indicates that there is a small, dense, positively charged part in the center of an atom? some uncharged particles are scattered by a gold foil. all uncharged particles are attracted towards a gold foil. all positively charged particles pass straight through a gold foil. some positively charged particles bounce back from a gold foil.