1
The symbol of copper atom is.........
2
Pb is the symbol of .........atom
3
The atom nucleus contains .........
4
The nucleus of.....atom doesn't contains neutrons
5
When atomic number of an element equals its mass number .this means that there aren't ..........in the nucleus of this element
6
Negative charged particles of negligible mass are.........
7
The particles which revolve around the nucleus of an atom of element are.........
8
The maximum number of energy levels in the heaviest known atom is.........
10
The rule 2n2 can't be applied to the ............energy level
