First of all write a balanced equation.
4Na + O2 -> 2Na2O
You are starting with a mass of sodium. You need to use sodium’s molar mass. Take this quantity times mole to mole ratio between sodium and sodium oxide to get moles of sodium oxide produced.
.141 moles of sodium oxide produced
Atomic mass Carbon (C ) = 12.01 a.m.u
12.01 g ---------- 6.02x10²³ atoms
1.50 g ----------- ??
1.50 x ( 6.02x10²³ ) / 12.01 =
7.51x10²² atoms of C
hope this helps!
200 is the answer let me know if you need anything