Which property of isotopes makes them suitable for determining the dates of ancient artifacts?

What is important to study for nios grade 12 chemistry? i have only one month left.

Write two balanced equations 1. dissolving of solid sodium hydroxide in water 2. the reaction of sodium hydroxide solution with hydrochloric acid

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.