WHEN A BEETA PARTICLE GOES OUT FROM A NUCLEUS IN RADIOACTIVE PROCESS , A PROTON BECOME EXCESS IN NUCLEUS SO IT SHOULD BE +VE CHARGED. BUT IT SHOULD BE NOT...WHY??

dear shantanu,

very nice and fundamental doubt. when we are dealing with nuclear reactions, we mean we are not having any electrons and they are accommodated accordingly with the atomic numbe (i.e., with proton number). During nuclear reactions, if a beta particle emission makes a proton excess, the overall nucleus is no more the same old one. But, it is new one with new proton and neutron number and when atom is formed by addition of electrons, it adds accordingly. as electron addition or removal is not a big deal ( about some eVs) when compared to nucleon addition/removal (in MeV range).

not a good comparison, this is something like when a boy is married to a girl and had a child, he is not just a son of their parents but is a father and a husband too. so what is the status earlier to nuclear reaction is not important.