Answer:
You won't be able to do it with the sum formula; instead, you'll need a structural formula.
Metals and salts do not exhibit intermolecular forces since they are made up of atoms rather than molecules. With a few exceptions, I assume you can detect salts and metals from the formula. Metal bonds and ionic bonds can be recognized as intermolecular if your text requires it.
When it comes to organic molecules, you should know that they always have Vanderwaals interactions between them. The larger the molecules, the more surface area they have and the more attractive Vanderwaals forces they have. However, you must learn more about all other forces. Depending on how the atoms are organized, a molecule containing electronegative atoms may or may not be polar.
Explanation:
