Positively charged particles of an atom are held together in the central region of the atom.
It is called nucleus. It is surrounded by electrons.
1. The volume of nucleus is small when compared to the volume of an atom.
2. The mass of an atom is concentrated in the nucleus.
3. The nucleus is positively charged which is different in magnitude for different elements.
4. In a neutral atom the number of electrons outside the nucleus are equal to the number of positively charged particles in the nucleus
