Please help I am not sure how to derive the formulas for the columns. Any help would be helpful!

1. Use the periodic table on D2L or period-table.org for the weight % oxide calculations 1. Pyroxene and Tourmaline (slide 21) 2. Use excel, ensure equations are in the cells. 1. You can do it on paper make sure all the steps are recorded. 3. How many Oxygens in Talc: Mg3Si4O10(OH)2 ? Tourmaline: (Na,Ca)(Fe,Li,Mg,Al)3(Al,Fe,Mn)6(BO3)3(Si6O18)(OH)3(OH,F,O) \begin{tabular}{|c|c|l|l|l|l|l|} \hline & & & Wolecular & Cation \\ \hline \end{tabular}