Final answer:
The correct empirical formula for a compound with a 1:1 ratio of elements is CO (carbon monoxide), which represents the simplest whole-number ratio of carbon to oxygen.
Step-by-step explanation:
The correct empirical formula for a compound with a 1:1 ratio of elements is CO (carbon monoxide). An empirical formula represents the simplest whole-number ratio of the elements in a compound. In the options given:
FeS2 has a ratio of 1:2 between iron (Fe) and sulfur (S).
CO has a ratio of 1:1 between carbon (C) and oxygen (O).
N2O has a ratio of 2:1 between nitrogen (N) and oxygen (O).
CF2Cl2 has a ratio of 1:2:2 for carbon (C), fluorine (F), and chlorine (Cl), respectively.
Therefore, the compound with a 1:1 empirical formula is CO.