Question

Alpha particles come closer to nuclei:
a.) Are deflected more
b.) Are deflected less
c.) Make more collision
d.) Are slowed down more

Answer 1

Hint: To answer this question we should know about the Rutherford Alpha Particle scattering experiment. We should know that in this experiment they used a gold foil.

Complete step by step solution:
So, first of all let us know about the Alpha Particle Scattering Experiment. We should know that, in 1911, Rutherford performed the Alpha Particle scattering experiment, which led to the birth of the nuclear model of an atom. We should know that, Rutherford took a thin gold foil having a thickness of $$\text{2}.\text{1}\times \text{1}{0}^{-\text{7}}$$m and placed it in the centre of a rotatable detector made of zinc sulphide and a microscope. We should know that they directed a beam of 5.5MeV alpha particles emitted from a radioactive source at the foil. In this experiment, lead bricks collimated these alpha particles as they passed through them.
We should know that, after hitting the foil, the scattering of these alpha particles could be studied by the brief flashes on the screen. Rutherford and his team expected to learn more about the structure of the atom from the results of this experiment. We should know that, after passing off alpha particles the alpha particles passed through the foil without suffering any collisions. And also, 0.14% of the incident alpha particles scattered by more than$1{}^{\circ }$. We can say that, around 1 in 8000 alpha particles deflected by more than$$\text{9}0{}^{\circ }$$.
When the incident alpha particle came very close to the positive mass in the centre of the atom, it would repel leading to a deflection. On the other hand, if it passes through at a fair distance from this mass, then there would be no deflection and it would simply pass through.
So, from the above discussion we can say that when alpha particles come closer to nuclei they deflected more. Because, positive mass is concentrated in the nuclei and alpha particles are positive, that’s why we can say that alpha particles are deflected more when they come closer to nuclei. So, our correct answer is option A.

Note: From the above experiment, we can say that most of the atom is empty space. We should note that this explains why most alpha particles went right through the foil. And, these particles are deflected or scattered through a large angle on coming close to the nucleus. Also, the electrons having negligible mass, do not affect the trajectory of these incident alpha particles.