Question

What does atomic nature mean?

Answer 1

the nature of the atom : size , shape , abundance etc.

Answer 2

http://en.wikipedia.org/wiki/Atom

Answer 3

It means things are not infinitely divisible. ("Atom" is from the Greek meaning "uncuttable.") Everything is made of tiny identical units, which cannot be changed, but only hooked together in various ways.

On first glance, the idea that everything around us is made of atoms is nuts. There appears to be an infinite variety of things -- trees, people, smoke, steel, blood, chocolate, coffee, stone, ocean water -- and it's absurd to think either that each and every one of them is made of a certain type of atom (people atoms, steel atoms, chocolate atoms), or that someone when you mix stone and water atoms you get something that is not midway between stone and water, but living flesh instead.

Hence when people first started thinking about of what the world was made, they quite naturally assumed it was made of continuous stuff, which could have its properties varied subtly in infinite numbers of ways, like a skein of yarn can be dyed in an infinite variety fo shades of color. The idea that things were made of atoms, which certainly had occured to ancient thinkers, particularly the Greeks, was dismissed as silly.

In fact, it was only the advent of repeatable chemistry in the 18th and 19th century that brought the idea of atoms back into study, because the regular patterns of chemical reactions are simply impossible to explain without assuming materials are made of atoms. (If things were NOT made of atoms, you would expect little in the way of patterns in chemical reactions -- things could react with each other in an infinite variety of ways, since matter could take on an infinite variety of forms.) Later on, in the late 19th and early 20th century, there was also physical evidence for the existence of atoms, particularly in the observations of gases and Brownian motion.

What we are left with, then, is explaining how it is that an atom of stone, e.g. a carbon atom, and an "atom" (or what we now call a "molecule") of water can combine to form a substance (living flesh) that has properties utterly unlike those of the stone or water. This is, indeed, the essential surprise of chemistry: that the products of chemical reactions can and usually do have properties utterly unlike the reactants.