Question

Why did some of the particles get deflected in Rutherford's experiment?

They hit the nucleus of the gold atoms
They were deflected by the negative electrons
They weren't shot with high enough velocity
None of the above

Answer 1

the alpha particles hit the positively charged nucleus of the gold atom thus they got deflected.

Answer 2

The reason as for why some of the particles got deflected in Rutherford's experiment was because some of them had hit the nucleus of the gold atoms.