The Building Block of the Universe: Atom

The basic building block of the known universe, which is the foundation of our bodies, the planet we live on, and even the stars, is the atom. Atoms come together to form molecules, which in turn form larger structures, from living things to building materials, from trees to technological devices, from rocks to planets and even stars, everything is made up of atoms.

When did we first think about or see these pieces when most atoms were about 100 picometers, or 10 billionths of a meter?

The first person to use the word atomus was the Greek scientist Democritus, who lived in the 440s BC. 2500 years ago, Democritus talked about the atom and the unchanging, indivisible essence, although he based his teacher's theoretical thoughts about atoms on very different foundations than the atom we understand today.

The modern atom was first discovered in 1803 by John Dalton, who looked at chemical reactions and suggested that matter consists of countable but indivisible parts called atoms.

In 1911, Ernest Rutherford discovered a model close to today's atomic model, that is, the mass and content of the atom, and named the positively charged particle that forms the nucleus a proton.

Today we know that at the center of an atom is a nucleus consisting of protons and neutrons. Around the nucleus, much smaller electrons move in specific orbits. Protons are positively charged, electrons are negatively charged, and neutrons have no charge. These balanced structures determine the basic properties of matter.

And the elements we know are just classified according to the number of protons they have, for example, the hydrogen atom has only one proton, the oxygen atom has eight, carbon has 6, lead has 82, uranium has 92. So we learned the order and place of the elements in the periodic table.

The majority of the atom is actually empty space. When we consider the nucleus and electrons, there is a big difference between the volume of the nucleus and the overall volume of the atom. As a general analogy, if the atom were the size of a football field, the nucleus would only be the size of a football, so the nucleus is known to take up about 1/100,000 of the space inside the atom.

Electrons, on the other hand, are much smaller in mass than protons and neutrons, but since they do not stay in place, it is very difficult to determine their exact volume, but since electrons revolve around the nucleus, they are the basic element that determines the volume of the atom. Since they do not stay in place and do not revolve in fixed orbits, the modern quantum atomic understanding accepts a possible settlement region that indicates where electrons can be found around the nucleus, and calls this region the electron cloud.

Although the atom appears to be almost entirely filled with an electron cloud, this space is actually mostly empty space because the electrons are so small.