The symbol for a certain isotope of radium is . How many nucleons are there in the nucleus of this isotope?
A) 88
B) 138
C) 214
D) 226
E) 314

Question

The symbol for a certain isotope of radium is  . How many nucleons are there in the nucleus of this isotope?
A) 88 
B) 138 
C) 214 
D) 226 
E) 314

Quizplus · Accepted Answer

The number after "Ra" in the symbol represents the atomic number, which is the number of protons in the nucleus. The subscript represents the mass number, which is the total number of protons and neutrons in the nucleus. Therefore, for the isotope of radium given in the symbol, the mass number is 226 (as indicated by the subscript) and the atomic number is 88 (since radium has an atomic number of 88 in the periodic table). The number of nucleons (protons + neutrons) in the nucleus is therefore 226.

The Symbol for a Certain Isotope of Radium Is