Inert gases are gases that don't react with other elements. What this means is that they won't combine with other elements, and trigger chemical reactions. I've posted a picture of the Periodic Table. Take a look at the VERY LAST row, all the way on the RIGHT side of the table. That row is made of up NOBLE GASES (He, Ne, Ar, Kr, etc.) Those noble gases are INERT. They are non-reactive.
They were Native Americans.
To find them you would have numbers of the elements in percentage or grams then you divide them by their molar mass to get their moles. From there you divide by the smallest number. Round it to two or one sig fig. If you have a number that is for ex. 2.5 you multiply it by 2 to make it whole as well the other whole numbers. Then to find the molecular formula the problem must give you another molar mass and using your empirical formula convert it to its molar mass then you divide them, larger number over smaller number. You should get a number round it to 1 sig fig. Now you use that number and multiply the subscripts on the empirical formula to get the molecular formula.
All of th above support the heliocentric theory.