Answer:
It has 5 neutrons
Explanation:
The fact that it is a neutral atom tells us that the number of electrons and protons is the same:
- The problem tells us there are 4 electrons, thus there are 4 protons.
The average mass of an atom is the sum of the number of protons and the number of neutrons:
- Mass = # Protons + # Neutrons
With the above information in mind we can calculate the number of neutrons:
- 9 amu = 4 Protons + # Neutrons
