Why beta particles are called as electrons as they are coming from nucleus?
It’s an archaic name. Beta particles are identical to any other electron. The name beta particle comes from the old descriptions of radioactivity. It was found that radioactive particles seemed to emit three different kinds of “radiation.” These were named alpha, beta and gamma radiation. In fact, since then, we have discovered that alpha and beta “radiation” are actually particles, not radiation. Gamma rays, in fact, did turn out to be radiation and is the standard term for that band of the EM spectrum now. In addition, we have also discovered many more modes of radioactive decay that emit particles and radiation other than alpha, beta or gamma, but these are probably the most common.
