Question

Solve this riddle: I am an atom with a mass number of 23 and 11 protons. I am a soft metal and react vigorously with water. Who am I and how many neutrons do I have? You can also create one such riddle.

Answer 1

The atom is sodium (Na), which has 11 protons and atomic number 11. Its number of neutrons is mass number minus protons: 23 − 11 = 12. Another riddle: I have 17 protons, a mass number of 35, and am used to disinfect water. Who am I? (Answer: chlorine, with 18 neutrons.)