Science & Tech

What is an atom

By Rachel Hartman
Info Guru,

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cool blue plasma ball
Atoms are the building blocks of all matter on earth
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You probably have heard of atoms and matter. Yet you may be wondering about what exactly an atom is. Atoms are at the heart of all matter. In other words, they form everything that exists in the universe, except energy. Here's a breakdown of what atoms are and how they function in the world.

Parts of an Atom

Atoms are incredibly small. They are so tiny that one speck of dust may contain up to three trillion atoms. Another comparison that can be made to describe the size of an atom involves a soccer ball. If one hydrogen atom, which is the smallest kind of atom, were the size of a soccer ball, then a whole soccer ball, with all the atoms that form it, would be about 4,000 miles tall.

Inside of an atom, you will find three different parts: protons, neutrons and electrons. In the center of an atom there is a nucleus. Protons and neutrons can be found inside of the nucleus of an atom. Electrons float around the nucleus in what is known as an electron cloud.

Protons have a positive charge. Neutrons have no charge, and electrons have a negative charge.

The number of protons inside of an atom is the atomic number. The atomic number often identifies the atom as an element. In a normal atom, the number of protons and electrons is equal. This is called a neutral atom.

Types of Atoms

There are many different types of atoms. In fact, there are over one hundred different kinds of these small particles. Each type is called an element. Some common elements are oxygen, helium and copper. The air around you consists of many different kinds of elements.

When different types of atoms are combined, they form what is known as a "compound." One of the most common compounds that you will find is water. Water consists of two hydrogen atoms and one oxygen atom.


When atoms create a compound, they share electrons. When electrons gain energy, they move away from the nucleus of the atom. Sometimes, there is also a large amount of heat involved. Heat causes the electrons to have a lot of energy and move further away. When they move so far away that they are really no longer part of the atom, we say that the atom is ionized. They electrons are so far removed that the atom is unable to bond with other atoms. This happens to atoms in stars.

Now that know how to answer the question: what is an atom. And you know how atoms make up matter. Look around you. Atoms form everything that you see. Your body, your chair, your food, and the glass in your window all consist of atoms.

Even though they are all around us, the question, "What is an atom?" is very common. We do not often think about the tiny, tiny particles that make up the universe. Yet they play a crucial role in everything that exists. The next time you see an object, think about the atoms that form it. Atoms are the very building blocks of all life and matter on the Earth and in space.

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