Why do different compunds made out of the same or similar atoms have fundamentally different properties?



Total chemistry noob here. I do kinda understand how compunds form, but why do they behave so different, e.g. even if just one out of 8 atoms is switched out for another while the rest stays the same.

In: Chemistry

Because of the shape of the atoms. Like carbon is used for both coal and diamond, but the shape of the diamond molecules is worth a lot more.

Fundamentally, much of that determines a compound’s properties is the shape of a molecule, as well as the different types of bonds formed.

Each element will form bonds of varying strength with each other element, so the order and positioning of atoms can drastically change the properties.

For example, a highly polar compound, where positive and negative ions are separated on either side of the molecule, will tend to have a higher melting and boiling point because each molecule will rotate until it’s strongly attracted to its neighbours. A compound with the exact same elements, but structured in such a way that it isn’t so polarized will have much weaker attractions.

The shape of the molecules, and what it’s components are, will largely determine the properties of the material. In a lot of cases, similar molecules will have similar properties, such as methanol and ethanol. In other cases, the difference is more dramatic (methanol and methane).