Intro to Atomic Theory and the Periodic Table

By Avaya Agarwal

Everything surrounding you right now is made up of atoms, small particles that are made up of even smaller parts. Atoms are one of the biggest ideas in chemistry, as everything builds onto atoms and their functions. Even the periodic table, the chart that is the base of everything in chemistry, heavily involves atoms in order to define elements and provide characteristics for them. Atomic theory and the periodic table are very important for any student to learn, especially when advancing their knowledge of chemistry.

What are atoms?

Atoms are the smallest units of matter. They are particles that consist of a nucleus surrounded by a cloud of electrons. The nucleus involves even smaller parts, called protons and neutrons. All chemical elements have atoms, as atoms are the basic particles that make up elements. Elements are things like oxygen, hydrogen, or fluorine, or the individual boxes that you see on the periodic table.

What is atomic theory?

Atomic theory was first proposed by scientist John Dalton, and it explains several concepts that are relevant in the natural world. It was the first complete attempt to describe all matter in terms of atoms and their properties. The theory has three parts to it:

1. Each element is composed of small particles that are indivisible and cannot be seen by the naked eye, called atoms. Atoms can neither be created nor destroyed.

2. All atoms of an element are alike in mass and other properties, but the atoms of one element differ from all other elements.

3. For each compound, different elements combine in a simple numerical ratio.

Even though this theory has not proven to be correct all the time, it still has not been proven useless or discarded because it correctly explains the law of conservation of mass and led to the creation of another law: the law of multiple proportions.

What is the periodic table?

As shown above, the periodic table holds all of the discovered elements and shows some of their properties. The table was created by Dmitri Mendeleev, and it quickly became an organizing icon of chemistry and is even commonly used in all other sciences. Some of the properties it holds include an elements atomic number, how many protons and electrons it contains, and its mass number, the mass of the element. There are many more properties that the periodic table shows as well, making it an extremely useful tool for chemists.