Na 2
ОО
20 points
What contains the protons and neutrons of an atom and also has most of the mass of an atom?
atomic number
electron cloud
nucleus
the period
3
20 points
An electron
has a positive charge, is inside the nucleus and has almost no mass.
has a neutral charge, is outside the nucleus and has a mass of lau.

Which of the following observations indicates that an atom has neutrons? some uncharged particles are scattered by a beryllium atom when it hits a gold foil. some uncharged particles bounce back from a gold foil when it is bombarded with alpha particles. a radiation consisting of uncharged particles is emitted when alpha particles strike beryllium atoms. a radiation which attracts electrons is produced when a beryllium atom is bombarded with alpha particles.