All elements want electronic structures like which group?

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.

Can someone me with 3 and 4 plz. this is for masteries test.

Write a balanced equation showing the formation of copper (ii) nitrite from its elements