Answer
See explanation
Work Step by Step
a. 40Ca2+ contains 20 protons and 18 electrons is correct. The atomic number of Calcium is 20, which means it has 20 protons, and 20 electrons. Ca2+ means that it lost 2 electrons, so it has only 18.
b. False. J. J. Thomson did the cathode-ray experiments; Rutherford discovered the nucleus..
c. An electron is heavier than a proton is incorrect. An electron is much lighter than a proton, with an electron having a mass of approximately 9.109 x 10^-31 kg and a proton having a mass of approximately 1.67 x 10^-27 kg.
d. The nucleus contains protons, neutrons, and electrons is incorrect. The nucleus contains protons and neutrons, while electrons are found in the electron cloud surrounding the nucleus.
