Question

When alpha particles are sent through a thin metal foil, most of them go straight through the foil because :

• A. alpha particles are much heavier than electrons
• B. alpha particles are positively charged
• C. most part of the atom is empty space
• D. alpha particles move with high velocity

Answer 1

Answer: (C), (D)

The correct options are
C

most part of the atom is empty space

D

alpha particles move with high velocity

Do you know what did Rutherford observed when he carried out $\alpha$-scattering experiment?

Rutherford observed that

(a) Most of the $\alpha$-particles ($99\%)$ passed through the gold foil undeflected.

(b) A small fraction of the $\alpha$-particles was deflected by small angles.

(c) A very few $\alpha$-particles (1 in 20,000) bounced back, that is, they were deflected by nearly ${180}^{\circ }$.

Therefore, option (a) (b) and (c) are correct.

Why did most of $\alpha$-particle go straight through the foil?

$\Rightarrow$ yes, by that observation he concluded that most of the space in an atom is empty.

And alpha particles move with high velocity that's why they didn't interact with an electron most of the time.

Therefore, option (c) and (d) are correct.