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?

  • $\begingroup$ Why do you think it never happens? $\endgroup$
    – Greg
    Nov 4 '17 at 18:00
  • 1
    $\begingroup$ I always thought this was because the alpha particle was ejected with too much energy to grab any electrons from its parent element's electron cloud. The alpha particle needs to be slowed down before it can grab electrons. I don't know if this is so, just what I assumed (presumed?). Or to put it another way, by the time any electrons could "feel" the alpha particle's influence, it was long gone. $\endgroup$
    – BillDOe
    Nov 4 '17 at 18:14

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.


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