Electron Cloud and 3+ important facts of the Electron Cloud Model

  • Electron cloud model
  • Electron cloud facts
  • who discovered the electron cloud ?
  • what are the energy levels of the electron cloud ?

Electron Cloud is a region surrounding nucleus in which high chance of electrons will be found.


The electron is

  • A negatively charged (free or bounded) particle an atom and charge on a single electron is a unit -ve charge.
  • The smallest and lightest of the particle in an atom.
  • Electrons are in constant motion as they circulate around the nucleus.
  • Electrons in atom lies in various specific spherical shells having various diameter, generally recognized as energy level, in which electron circulates.
  • The energy confined in the electron is become higher if spherical shells are greater.

Discovery Of The Electron:

• Sir William Crookes experimented in a vacuum using cathode ray tubes to understand the characteristics of hot metal.
• Electron was discovered by him in the year 1897, when he was observing the properties of cathode ray.

What is Proton ?


“a stable subatomic particle observed in most of the atom, with a +ve. electrical charged equivalent in magnitude to that of an electron.”

This is one of main constituents of atom. (with neutrons and electrons)

Example of proton

A single proton is found in the nucleus of a hydrogen atom.

Who discovered the Protons?

Proton Discovery

Protons has been observed as H+ by Eugen Goldstein (1886). In 1909, Ernest Rutherford has discovered alpha and beta particles too during an experiment ‘first splitting’ with uranium atom. He renamed “protons” based on the Greek word “protos” which means first, during that time, generally denoted by p+.  In the year 1911, Ernest Rutherford has discovered one of his famous invention of physics named ‘Atomic Nucleus’, from that start of modern physics has it’s new dimension.

What is Neutron?


a subatomic particle having approximately same mass as a proton but with out having any electrical charge (charge-free). This particle found in all atomic nuclei apart from ordinary hydrogen (H1).

Who discovered the neutrons?

James Chadwick invented neutron, used scattering data to calculate the mass of this neutral particle.

Who discovered the Protons?

In 1899, Rutherford discovered alpha and beta ‘rays’ from uranium. He later demonstrated that alpha rays are the nuclei of helium atoms. He discovered in 1914 that the nucleus of an atom constituted and extremely dense but small fraction of the volume of an atom and that this nucleus was positive in charge. The discovery of protons can be attributed to Rutherford.

Important Parameter of Atomic Particles

Important Parameter of Atomic Particles

Mass of the electron

The rest mass of the electron is 9.1093837015 × 10-31 kg.  This is 1/ 1836th times of proton.


Atoms are made up of a +vely charge nucleus encircled by electron clouds having -ve charged.

Generally, centralized nucleus is a collection of positively charged particles named proton, and neutral particle neutron, So, overall nucleus is +ve charged.

Binding Energy:

Binding energy is the minimum energy mandatory to disassemble or break the nucleus of an atom into its constituent parts.

Shape and Size of the Atom:

Some atoms are perfectly spherical. Though an atom does not have a distinct edge, since the electron density slowly falls off, where property you choose to quantify on those atoms is exactly the exact same regardless of what direction you consider the atom out of H2, He, Li, and Ne are typical examples of the atom.

The diameter of an atom varies from about 0.1 to 0.5 nm (1 × 10−10 m to 5 × 10−10 m) Therefore, an atom is a million times smaller than human hair.

What is in an Electron Cloud?

Electron cloud definition

An electron cloud is ​the area where chance of electron presence in -surrounding to an atomic nucleus is maximum. It is representing a region in which maximum probability of e- occurrence be there.

Electron Cloud
Electron Cloud

Who discovered the electron cloud ?

Electron cloud model by Erwin Schrödinger
Electron cloud model by Erwin Schrödinger

In the year 1920s, popular physicist Erwin Schrödinger projected that electron travels as waves. He also explained by an equation to calculate the probability of an electron to be existed in that area.

Atomic Models Electron
Atomic Models Electron Image credit : pixabay

Why is it called an electron cloud?

This model identified as electron cloud model as each orbital surround the nucleus of the atom be similar to a fuzzy cloud around the nucleus. The deepest area of the cloud is which e- having its highest chances to be present in that time. As it’s very similar to normal cloud and it’s of -vely charged electron, so acknowledged as electron cloud.

Erwin Schrödinger electron cloud model

Electron cloud model | cloud model of the atom

Electron cloud discovery

Niels Bohr has introduced the atomic Hydrogen model in the year 1913, by describing the positively charged nucleus is in the center, and having proton and neutron in that centralized location, and -ve electrons stays surrounded to that nucleus. For this model, the electron under normal conditions always stays at a certain distance from the nucleus and letter people has elaborated that electron location is not fixed though it’s position could be predicted, in where the chance is more to be existed called cloud or electron cloud.

3+ important facts of the Electron Cloud Model:

This model contained a solid nucleus having proton and neurons, that surrounded by a cloud of electron at various levels in orbital.

The deepest area of the cloud is somewhere the electron has the highest chances of be existing.

The move of the electron happens from negatively charged parts to ones that were positively charged. Any circuit’s negatively charged pieces have additional electrons, whereas the pieces want more, additional electrons. The electrons then jump to another level. The current can flow through the system when the electrons move.

How do electrons move in the electron cloud?

The e- try to move from negative charged parts to positive one as these are having excess electron, where as +ve one need more electron to full fill it’s orbital. So, e- will jump one zone to other ones, hence current also flows through in reverse direction.   

Does electron can fall onto nucleus?

Generally, electron never falls in the nucleus; However it is likely to force electron on top of the nucleus. An electron has to be accelerated employing a particle-accelerator (to energize sufficiently to overcome the repulsive force existed in-between these electrons working as a barrier) in order to produce a neutron, after completion of this process, e- could cross the threshold, fall in the nucleus and can interact with proton or neutron. If an e- of a H2 atom is to fall into its nucleus, will produce a proton.

Planetary vs Electron cloud model:

  • Bohr’s model treats electron energy level as evidently well-defined as an orbital path surround the nucleus (similar to a model, just like the way planet is encircling the Sun).
  • In the other way the cloud model treats the energy levels as probability of electron clouds, in which electrons are to be expected to exist in that area or regions.

Where is the electron cloud located ?

Planetary vs Electron cloud model
Planetary vs Electron cloud model
OpenStax College, 202 Two Models of Atomic StructureCC BY 3.0

Electron Properties | Electrons facts

Electron properties like a wave:

  • The electrons don’t orbit the nucleus at the way of a planet but rather exist as waves or clouds. Thus, is like a wave on a string’s frequency. Energy states are much like harmonics of the frequency.
  • The electrons are not in one point place, even though the likelihood of interacting with the electron in one point is discovered in the wave function of the electron. The charge on the electron behaves like it’s smeared out in space, square proportional to the magnitude of the electron’s wave function at any given stage in space.

Electron properties like a particle:

  • The electrons orbiting the nucleus should be an integer number.
  • In this concept, the e- jump as a particle at different pre-decided orbital. If energy and particle interact with the outer cell electron, the only electron will change its state in the response of interaction.
  • The electrons maintain particle-like properties; for example, every wave state has the same electric charge because of its electron particle. Each wave state has one distinct, discrete spin (spin up or spin down) determined by its superposition.

Electron cloud energy levels

Electron Orbit:

Electron Filling process : The Semi Regular Process
Image credit : Patricia.fidi, Public domain, via Wikimedia Commons

Here we will discuss,

How electron will fill in the cell structures ?  

Electron filling process

  • The e- will fill in-shell and sub-shells in a process called semi-regular process, as represented in above figure. 
  • The first shell level (an 1s subshell), will fill first.
  • Electrons move into the 2nd level 2s sub-shell and so on to the 2p sub-shells. Then a new shell 3s level will fill.
  • Though, 4s orbital will fill before the 3d cell, and later s orbitals fill in similar fashion too. (for example, the cell 6s will fill before filling the 4f cell because of these reason).
Electron filling process
Image credit : Patricia.fidi, Public domain, via Wikimedia Commons

How many electrons can be in each shell?

The highest no. of electron that can reside in a particular energy level:

Number of Electron = 2n2

Where, n signifies the Principal Quantum No.

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About Dr. Subrata Jana

I am Subrata, Ph.D. in Engineering, more specifically interested in Nuclear and Energy science related domains. I have multi-domain experience starting from Service Engineer for electronics drives and micro-controller to specialized R&D work. I have worked on various projects, including nuclear fission, fusion to solar photovoltaics, heater design, and other projects. I have a keen interest in the science domain, energy, electronics and instrumentation, and industrial automation, primarily because of the wide range of stimulating problems inherited to this field, and every day it’s changing with industrial demand. Our aim here is to exemplify these unconventional, complex science subjects in an easy and understandable to the point manner.
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