The Physics Question Bank

Rutherford scattering helped scientists understand what atoms are really like inside.

Before this experiment, scientists used the plum pudding model. This suggested that an atom was a ball of positive charge with negative electrons dotted inside it.

Rutherford’s team fired alpha particles at a very thin sheet of gold foil. Alpha particles are positively charged, so they are repelled by other positive charges.

Most of the alpha particles passed straight through the foil.

This showed that atoms are mostly empty space.

Some alpha particles were deflected.

This showed that there must be a positive charge inside the atom, because the positive alpha particles were being repelled.

A very small number of alpha particles bounced back.

This was the surprising result. It showed that the positive charge, and most of the mass of the atom, must be packed into a tiny central region.

This tiny central region is called the nucleus.

Rutherford’s experiment led to the nuclear model of the atom. In this model, the atom is mostly empty space, with a tiny, dense, positively charged nucleus in the centre and electrons around the outside.

AQA GCSE 4 mark answer

Rutherford’s team fired alpha particles at a thin sheet of gold foil. Most alpha particles passed straight through, showing that atoms are mostly empty space. Some alpha particles were deflected because the positive alpha particles were repelled by a positive charge inside the atom. A tiny number bounced back, showing that most of the mass and positive charge are concentrated in a small, dense nucleus.