An element has an atomic number of 92 and a mass number of 234. How many neutrons does the element have?
A. 192 B. 142 C. 92

Question

An element has an atomic number of 92 and a mass number of 234. How many neutrons does the element have?
A. 192	B. 142	C. 92

anonymous · Answer

The atomic number indicates the number of protons in the nucleus of an atom of the element, and the mass number indicates the total number of particles, neutrons and protons, in the nucleus.  To get the number of neutrons in an atom of that element, subtract the atomic number from the mass number;
234 - 92 = 142.  The answer is B.