SIMPLE MULTIPLE CHOICE PLEASE HELP!!!!!
 1.) In the Geiger-Marsden experiment, a thin gold foil was bombarded by 
 electrons
 alpha particles
 gamma rays
 2.) The chemical characteristics of an atom are determined by its:
 atomic number
 mass number
 binding energy
 number of isotopes
 3.) Calculate the speed of the electron of a hydrogen atom if it is in the fifth circular orbit.
 4.4 x 10^5
 1.1 x 10^7
 ANY HELP IS APPRECIATED!!!