What is an atomic number?

How important is atomic number in chemistry? Each element in the periodic table has its own atomic number. In fact, this number indicates how you can distinguish one element from another and distinguish between them.


The atomic number is simply the number of protons in an atom. That is why the atomic number is sometimes called the proton number. In calculations, the atomic number is denoted by the letter z. Z comes from the German word zahl meaning number or numerical or more modern than atomzahl meaning atomic number.

Because protons are the number of units of matter, the atomic number is always a natural number. Atomic numbers currently range from one (hydrogen atomic number) to 118 (the heaviest element atomic number known). As more elements are discovered, the atomic number will increase. Theoretically, there is no limit to the atomic number, but it should be noted that with the increase of protons and neutrons, the elements become more and more unstable and prone to radioactive decay. Decay may produce products with lower atomic numbers, while nuclear fusion produces atoms with higher atomic numbers.

In neutral atoms (in terms of electric charge) the number of electrons will be equal to the number of protons or the same atomic number.


The reason for the importance of the atomic number

The main reason for the importance of the atomic number is that by knowing it we can know the original atomic number of an atom. Another important reason is that today’s periodic table is based on increasing the atomic number.


Examples of atomic numbers

Regardless of the number of electrons and neutrons, any element that has a proton will be hydrogen. An atom with six protons will definitely be carbon, and an atom with 55 protons is also cesium.


Terms related to atomic number

If the number of electrons in the atom differs, the name of the element remains the same, but its ions will be produced. If the number of neutrons also changes, we will have a new isotope of that element.

Protons are found together with neutrons in the nucleus of an atom. The sum of the protons and neutrons of an atom will be the mass number of that atom (denoted by the letter A). The average sum of the number of protons and neutrons in a sample of an element is called its atomic mass or atomic weight .