Isomers

Same atoms, different arrangement, different substance. Compare the pairs, then try the drills.

Isomers are molecules with the same chemical formula but different molecular structures. Every atom is the same; what changes is which atom is bonded to which. That one change can move a boiling point by a hundred degrees or turn a liquid into a gas. Each group below shares one formula. Count the atoms in each drawing, then compare the properties.

Quick drill

Are these two the same molecule, isomers, or different formulas?

and

Isomers that differ only in space

These share not just the formula but the same bonds between the same atoms. They differ only in how the atoms sit in space, and they are still different substances.

Chiral or not?

Find a carbon with four different groups on it. Is this molecule chiral?