Question

beryllium (be) has an atomic number of 4 and an average atomic mass of 9.01. how many neutrons does beryllium have? 9 5 4 rewatch

Explanation:

Step1: Recall neutron count formula

$\text{Number of neutrons} = \text{Round(Atomic Mass)} - \text{Atomic Number}$

Step2: Round the atomic mass

Round $9.01$ to $9$

Step3: Calculate neutron count

$\text{Number of neutrons} = 9 - 4 = 5$

Answer:

5