What is the mass number of an atom with 7 protons, 8 neutrons, and 7 electrons?
Answer options with 4 options
A.
7
B.
8
C.
15
D.
22
The mass number of an atom is the sum of the number of protons and neutrons. In this case, there are 7 protons and 8 neutrons, so the mass number is 7 + 8 = 15.
Therefore, the correct answer is C. 15.