A neutral atom of beryllium (Be) has an average mass of 9 amu and 4 electrons. How many neutrons does it have?

13
9
5
4

Respuesta :

the answer is 5 subtract it

To find the number of electrons, just subtract the amu and the atomic number (aka number of protons or electrons)...

so it is...

9-4=5 neutrons

Brainliest plz! :)