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In looking at the structure of atoms to understand their properties, we have come up with two very powerful models. The first of these, the electron shell model developed in Concept Development Study 4, is based on observing the Periodic Law and the ionization energies of atoms. This led us to a model of the atom in which the electrons in an atom can be grouped together into “shells” with the electrons in a single shell seem to have similar energies. The second model is the quantum energy level description we observed in Concept Development Study 5. We observed that electrons in hydrogen atoms can only have certain specific energies, called energy levels. These two models seem quite similar. In both cases, it appears that the arrangement of the electrons in an atom can be understood by looking at the energies that the electrons can have.

But there are still many questions about how these two models are related. We developed the shell model by comparing the properties of different atoms, each with different numbers of electrons. We developed the quantum energy level model by looking mostly at hydrogen atoms, which each have only a single electron. We would like to know how the energy levels in a hydrogen atom are related to the electron shells in atoms with many electrons.

Perhaps the electrons in a single shell are in the same energy level, but we have not shown that. Even if we assume it is true, we still do not know what determines how many electrons can be in a single level. Without that, we do not know why each shell has a limit on how many electrons can fit. And if we don’t know that, then we don’t know why the properties of the elements are periodic.

To answer these important questions, we need to understand what it means for an electron to move about a nucleus. In the process of studying this, we will find that electrons move very differently than the ways in which we are used to particles moving. The results are surprising but they provide a firm foundation for understanding the Periodic Law of the elements.


In this study, we will assume that we know the postulates of the Atomic Molecular Theory and our measurements of relative atomic masses. We will also assume that we know that structure of an atom, with a tiny, massive, positively charged nucleus surrounded by a much larger empty space in which electrons move. The positive charge on the nucleus is equal to the number of protons in the nucleus and, in a neutral atom, is also equal to the number of electrons moving about the nucleus. We will assume knowledge of the concept of electron shells as a means of understanding the Periodic Law, which describes the chemical and physical properties of the elements.

From the previous Concept Development Studies, we shall also assume an understanding of Coulomb’s Law to describe the interactions of the protons and electrons in an atom. We will assume an understanding that light is an electromagnetic wave, meaning that, as it travels, the electric part of the light and the magnetic part of the light oscillate like a wave. And we shall also assume an understanding of the conclusions of our observations of the photoelectric effect. This means we understand that the energy of light is quantized into photons, or packets of energy, whose energy is proportional to the frequency of the light.

Questions & Answers

what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Concept development studies in chemistry 2012. OpenStax CNX. Aug 16, 2012 Download for free at http://legacy.cnx.org/content/col11444/1.4
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