Quantum Number

What is Atomic Structure?

The composition of an element’s nucleus and how its electrons are arranged around it are referred to as the element’s atomic structure. Protons, electrons, and neutrons comprise the majority of the atomic structure of matter....

Atomic Models

Many scientists used atomic models to understand the structure of the atom in the early centuries. Each of these models had advantages and disadvantages of its own and played a significant role in the development of the modern atomic model. Scientists like John Dalton, J.J. Thomson, Ernest Rutherford, and Niels Bohr made the most noteworthy contributions to science....

Dalton’s Atomic Theory

John Dalton, a British Chemist proposed that every matter is made up of atoms. These atoms are indivisible and indestructible i.e. they can’t be broken down into smaller particles. He also suggested that all atoms of a particular matter are the same, but atoms of different elements differ in size and mass. This means atoms of each element are unique....

Thomson’s Atomic Model

Sir Joseph John Thomson was also an English chemist famous for his discovery of electrons known as Thomson’s Atomic Model, for which he also got the Nobel Prize. He conducted a cathode ray experiment to invent electrons. He proposed that atoms are like a sphere of positive charge with negative charge embedded in them. He named this atomic model as Plum Pudding Model....

Rutherford Atomic Model

Rutherford who was a student of J. J. Thomson discovered Nucleus which contained protons and neutrons inside it. This discovery made huge changes to the atomic structure. The observations made by Thomson in his experiment were used by Rutherford to propose his theory for atomic structure through an experiment called Rutherford’s Alpha Ray Scattering Experiment....

Bohr’s Atomic Model

Neils Bohr, a student of Rutherford proposed his model in 1915 to address the limitation of Rutherford’s Atomic Model. It is the most widely used atomic model and is based on Planck’s theory of quantization. It explains that electrons always move in fixed orbitals only, and they are not present everywhere in the atom. Bohr also explained that each orbit has a fixed energy level. An orbit is also called an Energy Shell. Rutherford only explained the nucleus of the atom while Bohr made changes to that model and added electrons and energy levels....

Quantum Mechanical Model of Atom

Quantum Mechanics is the branch of physics that deals with the motion and kinematics of microscopic objects. Since atoms are of below microscopic size and the limitations of Bohr’s Atomic Model motivated the scientists to give a more general and accurate atomic model based on Quantum Theory. The Quantum Mechanical Model of the Atom basically uses two following theories to explain the structure of the atom:...

Quantum Number

To describe the location of an electron inside an atom we need a set of 4 numbers known as Quantum Numbers. These Quantum Number helps in distinguishing different orbitals which contain electron. Orbitals that have a smaller number mean they are closer to the nucleus, have a smaller size, and have a larger probability of finding an electron. The four types of Quantum Numbers are listed below:...

Subatomic Particles

The subatomic particles are the particles that are present inside the atom, There are three subatomic particles that are,...

Isotopes

Isotopes are the atoms of same elements that have the same atomic number but different mass numbers. Example C-12, C-13 and C-14. Here all are Carbon atoms and have the same atomic number i.e. 6 but different mass numbers. This difference in mass numbers can be understood from their atomic structure....

Atomic Structure of Isotopes

The isotopes of an atom have the same atomic number which means that the number of protons are same. Also, their chemical properties are the same because their electronic configuration is the same. The difference in mass number arises due to the difference in number of neutrons present inside the nucleus. Hence, the atomic structure of isotopes comprises of the same number of electrons and protons but different number of neutrons. We can understand this with the example of isotopes of hydrogen illustrated below:...

Electronic Configuration of Elements

The Electronic Configuration of Elements refers to the arrangement of electrons in different energy levels. The rule for the arrangement of electrons is governed by the following three laws:...

Summary – Atomic Structure

Atom: The defining structure and basic units of matter of an element are called atoms. The term “atom” came from a Greek word that means indivisible because earlier atom was thought to be the smallest things in the universe that could not be divided Atomic Structure: The structure of an atom comprising a nucleus, in which the protons and neutrons are present. The negatively charged particles called electrons revolve around the center of the nucleus. Nucleus: A collection of particles called protons and neutrons is called Nucleus. Protons are positively charged and neutrons, are electrically neutral. Protons and neutrons are made up of particles called quarks. The chemical element of an atom is determined by the number of protons, or the atomic number, Z, of the nucleus. Proton: Positively charged particles found within atomic nuclei are given the name Proton. Rutherford discovered the proton in his famous cathode ray experiment that was conducted between 1911 and 1919. Protons are about 99.86% as massive as neutrons. The number of protons in an atom is unique for each element Electron: Electrons are very tiny compared to protons and neutrons, about 1800 times smaller than either a proton or a neutron. Electrons are just 0.054% as massive as neutrons. Electrons were discovered in 1897 by Joseph John (J.J.) Thomson, a British physicist. Electrons have a negative charge and are electrically attracted to the positively charged protons Neutron: Rutherford theorized the neutron’s existence in 1920 and was later discovered by Chadwick in 1932. Neutrons were found during experiments where atoms were shot at a thin sheet of beryllium. Subatomic particles with no charge were released – and were named neutrons. Neutrons are uncharged particles found within all atomic nuclei Isotopes: Members of the same family of an element that all have the same number of protons but different numbers of neutrons are named isotopes. The number of protons in a nucleus determines the element’s atomic number on the Periodic Table. All the isotopes have unique properties, just like all family members have their own qualities....

Atomic Structure Class 11

The study of atomic structure in Class 11 (part of high school curriculum in many countries) introduces fundamental concepts that lay the groundwork for understanding chemistry and physics at a deeper level. These topics are not only foundational for Class 11 students but also essential for anyone studying chemistry or physics, providing a base for more complex topics in these and related fields....

Atomic Structure – FAQs

What is Atomic Structure?...