The chemical formula is established after chemical analysis.
Mg which stands for Magnesium is the element to begin with, not a compound.
There are only two.They are carbon and hydrogen.
The chemical name of the compound is often based on the names of the elements that are part of it. However, for many simple organic compounds it is not possible to determine the component elements.
The compound CH2O has 3 elements: Carbon (C), Hydrogen (H), and Oxygen (O).
The compound FeO is formed by two different elements: iron (Fe) and oxygen (O). In this compound, iron has a +2 oxidation state, while oxygen has a -2 oxidation state, resulting in a neutral compound.
2 elements
3
A compound forms when two or more different elements chemically bond together. Therefore, at least two elements must be present for a compound to form.
how many atoms are in this compound
Mg which stands for Magnesium is the element to begin with, not a compound.
There are two elements in the compound Fe2O3. These are: iron and oxygen
At least one. (That's not, entirely, a smart-aleck answer. I suspect you don't understand the meaning of either element or compound or possibly both. You need some review study, and trying to figure out how "one" is a legitimate answer should provide that. As a hint, consider the diatomic gasses, or buckminsterfullerene.)
Two: lead and iodine.
There are only two.They are carbon and hydrogen.
There are 3 elements in the compound C6H12O6: carbon (C), hydrogen (H), and oxygen (O).
The chemical name of the compound is often based on the names of the elements that are part of it. However, for many simple organic compounds it is not possible to determine the component elements.
A compound is composed of two or more elements. A compound of only two elements is a binary compound.