Two neutral atoms have the same total number of protons, neutrons and electrons. Atom P has 12 protons and 13 neutrons. Atom Q has 11 protons.
What is the neutron number of Q, and how does its approximate mass compare with P? Ignore electron mass.
14 neutrons; Q has approximately the same mass as P.
15 neutrons; Q has approximately the same mass as P.
15 neutrons; Q is heavier by one relative mass unit.
13 neutrons; Q is lighter by one relative mass unit.
103 exam-style questions on Edexcel GCSE Physics 6.1 Atomic structure and isotopes, covering 6.1.1 Structure of the atom, 6.1.2 Isotopes: atomic and mass number, 6.1.3 Sub-atomic particles: masses and charges, and 6.1.4 Electron orbits and energy changes. Each one has a worked solution and a mark scheme showing where the marks go.