Answer
$CH_{2}$
Work Step by Step
If we count the total number of atoms of Carbon and hydrogen present in the given diagram, we will get the molecular formula of cyclopropane which is $C_{3}H_{6}$. To find the empirical formula, we divide the molecular formula to get the simplest ratio. Thus, if we divide by 3, we get 1:2 and the empirical formula will be $CH_{2}$
