The Amazing Universe

Atoms Are Small. But How Small?

This is a very simplistic description of atoms. They are very complex objects.

British spelling.

The information in my articles has been gained by reading many books on the subject. I won't pretend to be an expert, but I hope you find some of my reads interesting.

Atoms are the smallest particles of chemical elements.

They are the basic building blocks of everything that can be seen or touched, including me and you and every other living thing on our planet.

Apart from a hydrogen atom which has just one proton and one spinning electron, other different types of atoms are made up of various amounts of protons, neutrons and electrons.

A chemical element is a pure substance made of atoms that have all the same number of protons in their nucleus, and the number of protons is known as their atomic number.

The mass of an atom is the total number of protons and neutrons combined. To give you an idea of the size of an atom and how small they are, take a human being of say 70 kilograms in weight, the total number of atoms making up that person's body is estimated to be 7 octillion, which is a staggering 7,000,000,000,000,000,000,000,000,000 atoms!

During our lives, vast amounts of atoms keep joining and leaving our bodies.

The most common atoms by mass that make up 99% of the human body are oxygen, carbon and hydrogen. When we die all the elements which we were made of will dissipate over time, eventually becoming part of other objects or even other living things in the future.

Under normal conditions atoms cannot be destroyed, they just keep on being recycled.

A molecule is an electrically neutral group of two or more atoms held together by chemical bonds, they can be simple or complex. To give an example, a water molecule consists of one oxygen atom and two hydrogen atoms bonded together. A carbon dioxide molecule consists of one carbon atom and two oxygen atoms bonded together.

Matter is the term used for material that takes up space. It is all around us. Matter is the air you breathe, the shoes you wear, the water in your glass and everything you can touch and smell. It is what we are.

Anything that has mass is matter and the three most commonly known states are solid, liquid and gas. The difference in the structure of each state is described as the densities of the particles.

It took roughly 380,000 years after the birth of the Universe for electrons to be trapped in orbits around nuclei, thus forming the first atoms. These new atoms formed the first low mass elements, mainly hydrogen and helium. Hydrogen is still the most abundant element in the Universe today.

As I said, a simple hydrogen atom contains just one proton at its centre and one spinning electron. So you could say that an atom is mostly empty space.

To give an idea of how far the electron could be from the nucleus of a hydrogen atom, then imagine this, scale the proton up to the size of a golf ball, at that scale and at certain times the electron could be as far as 2 kilometres from the centre of the atom, giving the atom a diameter of roughly 4 kilometres.

An atom can be 0.1 to 0.5 nanometers in diameter. There are 1,000,000,000 nanometers in one metre. Yes, they are extremely small.