A nuclide of potassium is represented by 1940K^{40}_{19}\text{K}1940K. Which row gives the number and location of the electrons in an atom of 1940K^{40}_{19}\text{K}1940K?
19 electrons, in the nucleus
19 electrons, surrounding the nucleus
21 electrons, in the nucleus
21 electrons, surrounding the nucleus
114 exam-style questions on CIE IGCSE Physics 5.1.1a Structure of the atom and ions. Each one has a worked solution and a mark scheme showing where the marks go.