The chemical formula for titanite is CaTi(SiO₄)O. To count the number of atoms of a particular element, you can look at the subscripts in the chemical formula. In titanite, the major element is titanium (Ti). From the chemical formula, you can see that there is one Ti atom present in each formula unit of titanite. For other elements like aluminum (Al) and iron (Fe), you would need to determine their presence in the compound based on its composition or impurities. If the compound contains additional elements like Al or Fe, their presence and quantity can vary depending on the specific sample or variation of titanite. It's worth noting that the chemical composition of natural titanite can vary, and impurities or substitutions of elements can occur, affecting the exact number of atoms of each element present. Analytical techniques such as X-ray diffraction or chemical analysis can help determine the specific composition of a given sample of titanite.