Silicon (Si) has three naturally occurring isotopes: 28Si, 29Si, and 30Si. Determine the number of protons, neutrons, and electrons in each silicon isotope. An unknown compound contains only C, H, and O. Combustion of 5.10 g of this compound produced 12.0 g of CO2 and 3.28 g of H2O. What is the empirical formula of the unknown compound?