Q. Assertion: Radioactive nuclei emit particles.
Reason: Electrons exist inside the nucleus.

 2355  247 AIIMSAIIMS 2003Nuclei Report Error

Solution:

Nuclear stability depends upon the ratio of neutron to proton. If the ratio is more than the critical value, then a neutron gets converted into a proton forming a particle in the process.

The particle ) is emitted from the nucleus in some radioactive transformation. So electrons do not exist in the nucleus but they result in some nuclear transformation.