Site developed by Steve Murov, Professor Emeritus of Chemistry, Modesto Junior College,

Some of the other Murov sites:
Chemistry Directory:
Organic Chemistry Directory:
Organic Solvent Properties and Property Directory:

I.  Traditional 
II. Vertical 
III. Toxicity (LD50 values) 
IV. Native (elemental form) 
V. Date and Country of Discovery
     History of Elements
VI. Formulas of Cmpds. with H and Cl 
VII. Reaction-Map of Organic Chemistry 
VIII.  Periodic tables with element colors    NEW
go to tables
IX  Internet Directory of Periodic Tables  
X.  Periodic Table Timelines    NEW
XI.  Organic Chemistry Milestones    NEW
XII. Unresolved Periodic Table Issues  

Dimitri Mendeleev

IX. Directory of Periodic Tables

    A. Properties, Graphing and/or Ranking Capability

WebElements - (choose topic from right side of site)  (chart, sort option did not work on 6/4/16)

    B. Properties 
electron configurations - 
nmr - 
x-ray - 

    C. Interactive and/or Animated Periodic Tables

    D. Images of Elements 

    E. About the Periodic Table

    F. Mendeleev and the History of the Periodic Table 

    G. Emission Spectra of Elements and Electron Structure 

    F. Isotopes 

    G. Chemogenesis (chemical reactivity from the periodic table) 

    H. Tabular Compilation of Elemental Properties and Abundances 

    I. Elemental Toxicities 

    J. Sources, Uses, Functions and Mineralogy of Elements

    K. Native Elements 

    L. Periodic Table Videos 

    M. Extended Periodic Table

    N. Vertical Periodic Table

    O. Periodic Table Printmaking Projects  

    P. Periodic Table of Comic Books, emojis and Haiku

    Q. The Element Song by Tom Lehrer  

    R. Periodic Table Templates

    S. Directories of Periodic Tables 


Questions about the periodic Tables

1. Suggest reasons for the predominance of the horizontal periodic table model over the vertical model but also suggest some advantages of the vertical model.

2. Which elements are sometimes referred to as the noble metals and why are they called noble metals? Is there any relationship of this terminology to the use of these metals in jewelry?

3. Of the elements with LD50 values for rodents reported, list the five most toxic. Does there appear to be any periodicity to toxicity? Explain your answer. (Note: a possibly relevant reference is:

4. Which of the native elements occur in nature in uncombined form (not as diatomics or bonded to themselves)? Is there a difference between the definition of an element and an elementary substance? (Note: a possibly relevant reference is Myers, R.J. J. Chem. Educ., 2012, 89, pp. 832-833.

Some periodic table questions and unresolved issues.

 1.  There are at least four commonly used versions of the periodic table:  the long, the medium-long, the left step, and the pyramidal.  While some experts have preferences for one or another, each has strengths and weaknesses.  Which one do you prefer and why?

medium-long and long (not up-to-date with names) (medium long and long but not up-to-date with names)

long form

medium-long form

left step

pyramidal version (not up-to-date with names)

2.  The positions of some elements in periodic tables are still disputed. 

a.  Does hydrogen belong in the alkali metals group or the halogen group or neither?

b.  There are some claims that second period elements have properties inconsistent with the remaining members of their groups.  Explain this statement.

c.  Some medium-long periodic tables have lanthanum part of the “f” group of elements (split out from the periodic table), others have lutetium as a member of the 14 elements and still others include 15 elements in the “f” group .  What is the best placement of these two elements?  Part of the issue is the priority of chemical properties versus electronic structure.  If electronic structure is taken as the determining criteria, are there other elements that are misplaced in the periodic table?


3.  The IUPAC numbers the groups from 1 through 18 but American periodic tables often have A and B group elements with the numbers running from 1A through 8A and 1B through 8B.  State the advantages and disadvantages of each and your preference (for a table with both, see tables above or:

 4.  Is the periodic table universal or could there be differences on another planet?  For example, consider the universality of atomic masses.

 5.  Does the periodic table contain any isotope information?  Consider use of the atomic mass as a source of isotope information (See:  S. Murov, Chem 13 News, March, 2010.  “Promoting Insight:  Atomic Mass”.

6.  The periodic tables above attempt to illustrate the approximate colors of the elements.  The orange staircase in the two periodic tables is commonly included in many periodic tables to very qualitatively separate the metals and the non-metals.  Do the colors of the elements also help to distinguish metals from non-metals and, if so, does this method correlate with the staircase model?  Which method do you think has more merit?  (Note:  It is often suggested that the elements adjacent to the staircase are metalloids, semiconductors and/or semimetals.  The consensus is that boron, silicon, germanium, arsenic, antimony and tellurium are metalloids with a few others in the questionable category.  For a discussion of criteria used to characaterize metalloid properties, please see: ).

7.  Calculations indicate that stability of nuclei depend on the neutron to proton ratio and predict an island of stability above atomic number 110.  Is it possible that there are some “longer lived isotopes” with atomic number above 110?  (e.g., see:

8.  What is the probability that elements with atomic number greater than 118 will ever be synthesized?
(e.g., see:

9.  In some cases, discoveries have been made virtually simultaneously by different people in different countries (e.g., 1772, 1963).   Is this just a coincidence or are other factors in play here?

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