Question

For Al, its atomic number is 13 and its mass number is 27. How many neutrons does it have?

OA 13
OB. 14
OC 26
OD. 27
O E 40

Answer 1

B. 14


Atomic mass is the addition of protons and neutrons. Atomic number is protons. If we subtract atomic number from mass, we get neutrons

Answer 2

14...................