An atom of aluminum (al) has an atomic number of 13 and a mass number of 27. how many neutrons does it have?

a) 13
b) 14
c) 27
d) 40

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

Iwill give extra points to who gets this right

Select each correct answer. more than one answer may be correct. which of the following is a characteristic of unicellular organisms? they can possess tissues and organs. all of their functions are performed by a single cell. they are usually microscopic. each of their cells is specialized to perform a specific function.