Answer:
10
Explanation:
Take a look to the chemical compound:
[tex]NaBO_3[/tex]
Which is Sodium perborate. Its chemical composition is:
[tex]Na=Sodium\\B=Boron\\O_3=Ozone[/tex]
In other words it has:
One sodium atom, one Boron atom and three oxygen atoms. Therefore, it has 5 elements in total.
However, as you can see the chemical compound has a coefficient of 2, so basically the number of elements of the chemical compound is multiplied by 2:
[tex]2*5=10[/tex]
Hence, the number of elements in [tex]NaBO_3[/tex] is 10
