What is an atom? Or what is the atom? Many people don’t know the answer; or they don’t know how to explain it!
By definition, an atom is “the smallest part of an element which cannot be further divided without the element losing its properties”.
But before you can understand this definition completely, you must understand what an element is. An element by definition “a substance which is made up of only one type of atom”.
Now here is where things get complicated: to understand what is an atom, you need to first understand what is an element; but to understand what is an element, you need to first understand what is an atom”. Sounds confusing? Don’t worry, just keep reading and the terms will soon lose their mysteries.
Let’s take water for example. Water is not an element, it is a compound. Water is a compound because it consists of two kinds of atoms: hydrogen atoms and oxygen atoms. You can guess then that hydrogen is an element and oxygen is an element. Hydrogen and oxygen are two elements, which, when combined, forms the compound called “water”.
(Related: what conditions are necessary for hydrogen and oxygen atoms to combine?)
The periodic table of elements lists all the elements discovered so far on earth.
Most of the substances you see around you are not elements, but compounds which are composed of two or more elements combined. The elements combine because of the properties of their atoms; and we will discuss the properties of the atoms of various elements later.
Getting back to the point, what exactly is an atom? Think of it this way…. Let’s imagine that you have a piece of solid element in your hand, in the shape of a bathing soap. Imagine for a moment that the bathing soap is an element. In fact, the bathing soap is not made up of one element, but several elements. Nevertheless, imagine for a moment that the bathing soap is made up of one element.
Now imagine you take a knife and cut the bathing soap in half. Now you take on of the halves and cut it into half again. You keep repeating this process until you have a piece of soap so tiny that you cannot see it. However, you use a powerful microscope and a magical knife to further cut this tiny piece of soap so many times further that it is not possible to cut it any further. This smallest piece of soap that cannot be cut any further can be compared to an atom.
Initially scientists declared that it is impossible to further divide an atom into smaller parts; and the word atom itself means “indivisible”.
(Related: Splitting the atom: Mankind’s Will to Stay Alive)
Later on however, genius scientists were able to “split” the atom and produce large quantities of energy in the process. This process was first put to use in the making of the atomic bomb.
Nowadays, mankind still split the atom to produce large quantities of energy; but they put it to more productive use, such as generating electricity.
(Bear in mind that when an atom is split, it ceases to exist)
Even though the atom is the smallest part that an element can be divided into, scientists have identified even smaller parts that make up each atom: protons, neutrons and electrons. These smaller parts of the atoms are called “subatomic particles”, and I guess you can understand why.