Consider an atom of carbon in which the nucleus contains 6 protons and 7 neutrons. What is its atomic number and atomic mass number?
A)atomic number = 6; atomic mass number = 13
B)atomic number = 6; atomic mass number = 7
C)atomic number = 7; atomic mass number = 13
D)atomic number = 13; atomic mass number = 6

Question

Quizplus · Accepted Answer

Atomic number is the number of protons in the nucleus of an atom, which in this case is 6. 
Atomic mass number is the sum of protons and neutrons in the nucleus of an atom, which in this case is 6+7=13. Hence, the option A is correct.

Consider an Atom of Carbon in Which the Nucleus Contains