Question

how many neutrons are in the nucleus of an atom with an atomic mass of 80 amu and an atomic number of 35?
a 35
b 45
c 80
d 115

Explanation:

Step1: Recall the formula

Atomic mass = Number of protons + Number of neutrons. Atomic number = Number of protons.

Step2: Calculate neutrons

Number of neutrons = Atomic mass - Atomic number. Given atomic mass = 80 and atomic number = 35. So, number of neutrons = 80 - 35 = 45.

Answer:

B. 45