What atom has the largest atomic radius barium calcium magnesium radium

In the 1800s, one of the statements in john dalton's atomic theory was that atoms are indivisible. later experimental evidence led to the discovery of subatomic particles such as neutrons, electrons, and protons. what happened to the indivisible atom part of dalton's atomic theory, and why?

Fill in the coefficients that will balance the following reaction: a0cr2(so4)3 + a1agno3 -> a2cr(no3)3 + a3ag2so4

What is the molarity of the solution produced when 145 g of nacl is dissolved in sufficient water to prepare 2.75 l of solution?