Chemistry 9th Edition

We begin by calculating Mendeleev's propose mass for indium. Because for every gram of oxygen, there are 4.784 grams of indium, the total mass of indium in indium oxide ($In_2O_3$) is 4.784*(3*16.00) = 228.632. This mass is composed of two indium atoms; therefore, the atomic mass of one indium atom is $228.632/2=114.8$ amu. The second formula is $InO$. Because for every gram of oxygen there are 4.784 grams of indium, and the compound contains 16 grams of oxygen to begin, we have $4.784*16=76.544$ grams of indium in indium oxide. This mass is composed of one indium atom; therefore the atomic mass of indium for the second formula is $76.54$ amu.