What is an Atom : Structure and Its Properties

An atom is present in everything we observe around us. Every living creature and nonliving things are composed of atoms where nonliving things made up of the matter. But the atom is the basic building block of matter. So, everything is composed of atoms. The term ‘Atom’ is a Greek word and the meaning of this term is indivisible. Greeks believed that matter can be crashed into extremely small unseen particles which are known as atoms. The concept of the atom is described by Greek philosophers namely Democritus & John Dalton. A philosopher like Democritus has explained the concept of matter and also projected that all materials are made up of the matter. He confirmed atoms are continually moving, unseen, tiny particles that are dissimilar in outline, dimension, and temperature & cannot be smashed. This article discusses an overview of the atom structure.

What is an Atom?

Definition: The fundamental units of substance, as well as the important structure of elements, are called atoms. As the name is taken from the Greek word for indissoluble, as the atoms are the smallest things available in the space & could not be separated. These are invented with three particles like electrons, protons & neutrons which are created with even minor particles namely quarks. The important elements are hydrogen, helium, nitrogen, iron, carbon, chlorine, aluminum, and gold.


Atom Structure

The atom structure mainly includes two regions namely the center region and outer region. The center region (nucleus) of the atom includes protons & neutrons whereas the outer region includes electrons in orbit in the region of the nucleus. The mass of protons & neutrons within the nucleus has approximately 1.67 × 10-24 grams. Every electron in the outer region has a -ve charge (-1) that is equivalent to the +ve charge (+1) of a proton.

Atom Structure
Atom Structure

The elements like Neutrons are uncharged those are found within the nucleus. Atoms are the smallest units that hold different chemical properties of an element. Atoms merge to form molecules to interact with solids, liquids, or gases. For instance, water can be composed of oxygen and hydrogen atoms and both the atoms will combine to form molecules of water.

The mass of electrons is much lesser compare with protons like 9.11 × 10-28 grams. Researchers identify this amount of mass like 1 AMU (atomic mass unit) otherwise 1 Dalton. Thus, they do not donate much overall atomic mass of the element. In atomic mass, it is normal to disregard the mass & mass of the electron of atoms can be calculated based on the no. of protons & neutrons.

Electrons donate very much to the atom’s charge because every electron has a negative charge -1) that is equal to the positive charge (+1) of a proton. In neutrons atom, the orbiting electrons around the nucleus are equivalent to the no. of protons within the nucleus.

  • The particle-like proton charge is +1, mass is 1amu, and located in the nucleus.
  • The particle-like neutron charge is 0, mass is 1amu, and located in the nucleus.
  • The particle-like electron charge is -1, mass is 0, and located in orbitals.

Atomic Energy

In 1930–1940, scientists found that if the bomb uranium including a neutron, then the nucleus will split into two types. When this occurs energy can be set free, known as nuclear fission.

The first nuclear fission was used in atomic bombs. In the Second World War, the Americans dropped these bombs over Japan country. The atomic bombs produced so much energy to kill thousands of people. Afterward, scientists investigated how this energy could be utilized in a nonviolent way. In the year 1950, the first atomic reactor was designed and they generate energy by dividing atoms.

Properties of an Atom

The properties of an atom include atomic number, electric charge, size, radioactivity, atomic mass, subatomic elements, forces in the atom, atom stability, the nuclear force, atoms, molecules & matter in bulk.

Atomic Number

The atomic number is nothing but the protons number within the atom. For instance, the atomic number of hydrogen is 1 so it includes one proton. In nature, elements with 92 automatic numbers can also found because these are formed by scientists in a laboratory..

Atomic Mass

The no. of protons & neutrons present in an atom is known as atomic mass. Atoms with a similar element have a similar no. of protons. Sometimes, they have more neutrons so such kind of atoms is known as isotopes.

For instance, element like hydrogen includes 3 isotopes. Usually, it includes 1 proton & 1 neutron. In some cases, we can find hydrogen isotopes including 2 or 3 neutrons, however, they too have just one proton.

In lighter elements, each atom’s nucleus includes the same no. of neutrons & protons whereas, in heavier elements, they include fewer protons than neutrons. For example, Uranium includes 92 protons & 146 neutrons; the atomic mass of uranium is 238.

Electric Charge

Usually, an atom can be neutral electrically. However, it can lose or gain electrons once it collides with new atoms. Once this gains or loses an electron is known as an ion that includes an electric charge. When an atom loses electrons then it will become positive ions whereas the atom gains electrons then it will become a negative ion.


The nucleus in some atoms will be changed naturally is known as radioactive. Once a nucleus alters then it will produce rays. The radioactive elements in nature are radium or uranium.


1). What is an atom?

An atom is a basic part of matter and is made up of three small types of particles like protons, electrons, and neutrons.

2). What are the different kinds of atoms?

They are stable, isotopes, Radioactive, ions, and Antimatter.

3). Can we see atoms?

No, they are invisible

4). What is the center of an atom?

The center of an atom is called nucleus which includes protons & neutrons.

5). What is the size of an atom?

The size of the atom is 100 picometers

Thus, this is all about an overview of the atom structure.  It is the most essential element of daily life. All the elements are invented with atomic physics which includes electrons, protons & neutrons. The world is made up of matter & matter is made up of atoms. Hence the whole universe is made up of atoms. At present, atom physics is one of the most significant topics because it has the authority to control society in the present or the future. Here is a question for you, who invented an atom?