Why do Alpha particles not collide with electrons during alpha decay? Alpha particles are positively charged, so my question is that during alpha decay, when these are released from the nucleus, why doesn't it ever occur that they collide and grab an electron or two since they are essentially a Helium nucleus?
Actually they do collide.  But, the emitted alpha particle carries much more energy than the binding energy of the electron(s) in a helium atom or $\ce{He^+}$ ion.  Therefore such a collision scatters the electrons (which carry away some of the original energy of the alpha particle) instead of forming an atom.