Why radius of alpha particle is more than radius of He+ ?
Why radius of alpha particle is more than radius of He+ ?
In a same period, the outer-most shell (or the valence shell) remains the same. In this particular case, is the S1 orbit. But since there are one more proton in the helium atom, the electromagnetic force exerted onto the electron is greater than the force of one proton. Therefore, since the inward pulling force (if you like) is greater, the radius of the valence shell shrinks. This can generalize to all atoms. In one single period, the atomic radius always shrink as the group number increase (or as the atomic number increase), thus exerting more force on the electrons. Though when a new electron orbit is added (which happens when one move down a period), the atomic radius will increase.
In conclusion, the shrink of the atomic radius is due to the the increase of the force of the extra proton in Helium Atom compare to the alpha particle.
In a same period, the outer-most shell (or the valence shell) remains the same. In this particular case, is the S1 orbit. But since there are one more proton in the helium atom, the electromagnetic force exerted onto the electron is greater than the force of one proton. Therefore, since the inward pulling force (if you like) is greater, the radius of the valence shell shrinks. This can generalize to all atoms. In one single period, the atomic radius always shrink as the group number increase (or as the atomic number increase), thus exerting more force on the electrons. Though when a new electron orbit is added (which happens when one move down a period), the atomic radius will increase.
In conclusion, the shrink of the atomic radius is due to the the increase of the force of the extra proton in Helium Atom compare to the alpha particle.
