Which of the following is the correct definition of an isomer?
◦ Isomers are molecules that have the same empirical formula but different arrangements of atoms in space.
◦ Isomers are molecules that have the same molecular formula but different arrangements of atoms in space.
◦ Isomers are molecules that have the same arrangements of atoms in space but different empirical and molecular formulas.
◦ Isomers are molecules that have the same molecular formula but contain different isotopes.
◦ Isomers are molecules with the same empirical formula but have different isotopes.