In the plum pudding model, an atom was described as
a tiny positive nucleus with electrons in shells
a lattice of alternating positive and negative ions
a solid neutral sphere containing no particles
a ball of positive charge with negative electrons embedded in it
46 exam-style questions on Edexcel GCSE Chemistry 2.1 Atomic structure, covering 2.1.1 Development of the atomic model, 2.1.2 Structure of the atom and subatomic particles, 2.1.3 Mass number, isotopes and relative atomic mass, and 2.1.4 Calculating relative atomic mass from isotopic abundance. Each one has a worked solution and a mark scheme showing where the marks go.