Why does radius increase as you go down a group (hint: think Bohr-Rutherford diagrams)? Why would an increase in radius make it easier to lose an outer electron (i. e. give a lower ionization energy)?

Awhite powder is added to a solution. the images show observations made before the powder is added, just after the powder has been added, and a little while later. (the liquid in the small beaker is phenol red solution.) what evidence shows that a chemical change has taken place?