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PERIODIC TABLE
Lesson 2 - Page 3

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Valence shell configuration representation

Elements are composed of extremely small particles called atoms. An atom is the smallest part of an element that retains all the characteristics of the element. Atoms are composed of protons, neutrons, and electrons, which is composed of the basic building blocks of matter, leptons and quarks.  These subatomic particles lack the distinct characteristics of elements.

Protons and neutrons are made of different combinations of quarks. There are six different types of quarks known as flavors including up, down, charm, strange, top, and bottom.   Protons are positively charged, and neutrons are electrically neutral.  Neutrons and protons are found within the nucleus of an atom.

Negatively charged particles called electrons and are one of the six types of leptons.    Electrons are found away from the nucleus at distinct distances from the nucleus called atomic orbitals or energy levels.  Each of the orbitals can contain a set number of electrons, but it is difficult in this model to describe exactly where the electrons can be found.   

On the Periodic Table of the Elements you can determine orbitals looking at the Valence shell configuration.  This configuration is an advanced look into an elements atomic structure.  On the recommended Periodic Table, you can find this number on the lower right hand corner.  Atomic orbitals are mathematically derived and describe the motion and placement of electrons of an atom.  Early researchers thought that electrons used to orbit the nucleus similar to planets revolving around the Sun.  However, an electron is not solid like a planet, so the term orbital is now used instead of orbit.   The orbitals are named s (sharp), p  (principal), d (diffuse) and f (fundamental).  The usage of s,p,d, and f were used because of their relationship to spectral characteristics to determine the number of electrons.  However, spectral analysis is no longer used but chemists still keep the letters. 


Spectral characteristics of sodium and lithium compared to solar radiation.

 

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