An atom of Oxygen. Contains:
Protons = 8
Electrons = 8
Neutrons = Mass number - Number of protons = 18 - 8 = 10
Neutrons = 10.
For this, we first calculate molecular weight of MgSiO₃:
Atomic masses:
Mg = 24
Si = 28
O = 16
Mr = 24 + 28 + 16 x 3
Mr = 100
moles = mass / Mr
moles = 237 / 100
moles = 2.37
The ionic formula of sodium oxide would be Na20
I think it is the letter A because they both Make sense