Scientists found that the mass of a nucleus is greater than the total mass of the protons it contains. The charge of the nucleus is equal to the total charge of those protons.
Which change was made to the nuclear model of the atom to explain this evidence?
More protons were placed in the nucleus than first thought.
Particles with no charge were added to the nucleus.
The positive charge was spread through the whole atom.
Electrons were placed in the nucleus with the protons.
101 exam-style questions on OCR GCSE Chemistry 1.2 Atomic structure, covering 1.2.1 Development of the atomic model, 1.2.2 The nuclear model and the size of atoms, and 1.2.3 Subatomic particles in atoms and ions. Each one has a worked solution and a mark scheme showing where the marks go.