Created By : Rina Nayak

Reviewed By : Phani Ponnapalli

Last Updated : Apr 24, 2023

The atomic number is always whole integers of (protons, neutrons, and electrons). The total number of subatomic particles in an atom (A-Z) is equal to the sum of the mass number and the atomic number. The mass number indicates the mass of the nucleus of an atom in atomic mass units (amu). Use our Atomic Mass Calculator and quickly determine the atomic number of any element in no time. Simpl, type in the element name and click on calculate button to get result.


What is an Atomic Number?

  • The atomic number of an atom is determined by the total number of protons in its nucleus.
  • It is represented by the letter 'Z.'
  • A certain element's atoms all have the same number of protons and thus the same atomic number.
  • Different elements have different atomic numbers.
  • For example, carbon atoms have an atomic number of 6, while oxygen atoms all have an atomic number of 8.

Atomic Number Examples

The atomic number is equal to the number of protons in an atom's nucleus or the number of electrons in an electrically neutral atom. The number of protons in an atom is known as the atomic number.

For example, A sodium atom has 11 electrons and 11 protons. As a result, the atomic number of the Na atom is 11 since the number of electrons equals the number of protons.

Atomic Number Orbital Energy Levels

When an electron is at a certain energy level, it is more likely to be found in some parts of that level than in others. These parts are known as orbitals. Sub levels are orbitals that have the same energy. A maximum of two electrons can be held in each orbital.

Using diagrams is the most popular means of demonstrating the distribution of electrons in an atom.

The number of electrons in each energy level must be written down. The atomic number of an element informs us how many electrons there are in the atoms. Carbon has an atomic number of 6, which translates to 6 electrons as 2,4. So an atom with the atomic number 12 has an electronic structure of 2, 8, 2, with two electrons in the lowest energy level, eight in the next, and two in the highest energy level. Looking at a lot of examples of these arrangements is the simplest approach to grasp them.

FAQs on Atomic Number

1. Why atomic number is used in the periodic table?

In the periodic table, the atomic number of a chemical element is used to organize the elements in order of increasing protons in the nucleus.

2. What is the distinction between atomic weight and atomic number?

Each atom can be assigned both an atomic number and an atomic weight (the number of protons equals the number of electrons) (approximately equaling the number of protons plus the number of neutrons).

3. What is the formula for calculating atomic percentage?

To calculate an element's mass percent composition, divide the element's mass contribution by the total molecule mass. To be stated as a percentage, multiply this amount by 100 %.

4. Why is carbon's atomic number 6?

Protons define the atomic number because of their positive charge, and six of them bound in an atomic nucleus equals six. As a result, carbon is produced. Carbon 6 is composed of 6 protons and 6 neutrons.