14Nov 2014 by Vincent Summers 3 Comments

Hydrogen Metal?

Chemistry
We're familiar with hydrogen as a gas, but hydrogen metal? Could it be that's what hydrogen is? [Artist's conception at right.] There are more than 100 substances listed in the Periodic Table of the Elements. This table is called "periodic" because, although each column is completely different, the properties of one row are very similar to the properties of the next. If you start on the left with an alkali metal, and you go through a row, you go to the next row and another alkali metal. An Anomaly Most of the alkali metals, such as lithium, sodium, and potassium, are very similar. They are soft, reactive, silvery solids. They have one outer electron and conduct electricity. They are easily cut with a knife. But, there is an exception ā€“…
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18Aug 2014 by Vincent Summers No Comments

Factors that Complicate Atomic Mass Determination

Physics
[caption id="attachment_8319" align="alignright" width="440"] Nucleus - CC-SA-3.0 by Marekich[/caption] Modern chemistry depends a good deal upon accurately knowing the atomic mass of each of the elements. What factors complicate determining those values? Each of the approximately 90 different natural-occurring elements possesses a nucleus or central core of protons and neutrons, in addition to electrons that orbit around the nucleus. It is important to the chemist or physicist to know the total mass of each element. Can correct values be obtained simply by summing the weight of individual particles in an atom? After all, each of these particles has a precisely known mass. The answer is, No! Such calculations disagree with experimental measurement. An example illustrates the point. Consider Helium-3 An atom of helium-3 has two protons, one neutron, and two…
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22Mar 2014 by Vincent Summers No Comments

What are Allotropes?

Chemistry
[caption id="attachment_6012" align="alignright" width="440"] Cyclooctasulfur (S8)[/caption] What are allotropes? An allotrope is one of a variety of forms in which an element can exist. This does not refer to the state of an element, whether solid, liquid, gas, or plasma. It refers to the tendency of an element to exist in different structural forms. Allotropes of Carbon Thus carbon can be found in a variety of forms, including graphite, charcoal, diamond, fullerenes, and nanotubes. Of Sulfur Sulfur allotropes take an assortment of forms. These include rings that range from six to twenty atoms. Especially well known are the monoclinic and rhombic crystalline forms. Of Phosphorous Phosphorus allotropes exist in a variety of colors. Ordinary phosphorous is called white phosphorous (Pā‚„). It is unstable and dangerous. But there are also red,…
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