Answer:
4. gives the relative number of atoms of each element per formula unit
Explanation:
An empirical formula -
It refers to the formula which determined the simplest whole - number ratio of all the atoms in a given species , is referred to as an empirical formula .
In simple terms ,
It is he smallest formula of the whole number which when multiplied by some whole number gives the actual structure of the compound .
Hence , from the given information of the question ,
The correct option for empirical formula is 4.