Isomers are compounds that have the same molecular formula. To determine whether two molecules are isomers, just count how many atoms of each type are in both molecules. If both molecules have the same count for all of the different atoms, the molecules will be isomers.
For example, consider the following molecules.
Count how many atoms of each type are in the structure on the left. Then count how many atoms of each type are in the structure on the right. Remember that each carbon needs to have a total of four
bonds, so fill in hydrogens where necessary.
to check your answers and continue on.