What is the mass number of an element if its atom contains 10 protons, 10 electrons and 12 neutrons? by Sunday | May 13 | Chemistry WAEC | 0 comments A. 32 B. 22 C. 20 D. 10 Correct Answer: Option B B. 22 Users Also Read These:The nucleon number and the proton number of a…An atom 17 protons, 17 electrons and 18 neutrons has…The nucleon number and the proton number of a…An atom X consists of 6 protons, 6 electrons and 7…The nucleon number and the proton number of a…