Currently, we can know and learn so much about chemistry, that there simply isn't enough time to learn in all!

Right now you can simply look at the textbook and find the meaning of multiple concepts, however, it wasn't always like this... there once was a time when books simply didn't have the meanings because they weren't discovered yet.

To learn how they were discovered let's take a trip through time!

Dalton's Theory - In 1808, Dalton wondered...

Hmm... I wonder what the things around us are made of?

To answer his question he developed the atomic model of the atom. He called it the invisible building blocks that made up 'matter':

Postulate 1: all matter (material) is made up of very small particles called matter

Postulate 2: An element consists of atoms of one type only.

Postulate 3: Compounds are made of more than one element and are made by combining elements in whole number ratios.

Postulate 4: In a chemical reaction, atoms aren't created or destroyed

He also proved the law of multiple proportions:

The laws of chemical combination were known by the scientific community in the 1800s and these laws such as law of definite proportion and conservation of matter worked to further prove Dalton's model.

If two elements X and Y combine in different ways to form more than one compound, the masses of X that combine with a fixed mass of Y can be expressed as a ratio of small whole numbers.

J.J Thomson's Plum Pudding - years later, Thomson started questioning Dalton's theory further

I wonder what atoms are made of?