Question

12. Which of the following species has the

least mass?
A. Electron C. Hydrogen ion
B. Helium atom D. Neutron
13. The mass number of an element whose
atom contains 13 electrons, 13 protons and
14 neutrons is
A. 13 B. 26 C. 27 D. 40
14. Which of the following elements exhibits
variable oxidation states and forms​

Answer 1

12.electrons

13.13

14.aluminum has 14 neutron.